A wireless charging device includes a charging battery, a transmitter coupled to the charging battery, and a controller coupled to the charging battery and the transmitter. The first and second hydromotor units can be adjusted in terms of their displacement via a first and second variation device. These discrete elements may include a multiplicity of granules, bristles, or projections and may be formed of materials having various properties such as hydrophilic characteristics. , and therefore damages are not inflicted on the cell transistor 17, and a ferroelectric process that conforms to a semiconductor process is provided. The sheet media are separated and conveyed while periodically changing the pressurizing force of the reverse roller against the feed roller.