The residual potential and charging potential of the surface of a photosensitive drum 20, or the charging potential and exposure potential of the surface of the photosensitive drum 20 are detected by an exposure sensor 28. The ink jet recording head comprises ink jetting orifices from which ink droplets are jetted, and ink paths connected to said ink jet orifices. An optional release film can be used in conjunction with the support film. During times when a sufficient amount of streaming data of the second set of data is available for communication, the second set of data is communicated to a user. The mobile device can then update the candidate locations using a next observation, and determine a probability density function based on the candidate locations.