| 摘要 |
<p>PROBLEM TO BE SOLVED: To keep a prescribed communication speed by use of a simple configuration and control even if radio wave strength weakens.SOLUTION: An image forming device measures radio wave strength and communication speed of a radio wave transmitted by a mobile terminal at a radio wave strength measuring unit and a communication speed measuring unit, and stores current communication characteristics (current characteristics) (step S22). If the current characteristics are deteriorated than pre-measured reference characteristics, the image forming device increases a reference radio wave strength F (step S25). In addition, if the radio wave strength of a radio wave received by the image forming device is lower than the reference radio wave strength F, and it has been decreasing consecutively for a reference time (step S26, S27: YES), the image forming device transmits a warning message to give advance notice of communication interruption to a mobile terminal 9 (step S28) to prompt a user to move the mobile terminal 9 closer to an image forming device 1.</p> |
