An apparatus for recycling asphalt pieces obtained from the repairing work site, to repair rapidly potholes and cracks in roadway and at a minimum cost, and of which it is possible to produce a usable hot asphalt at a temperature about \u221212 to \u221215 degrees Celsius. By adjusting the viscosity of the fluid through application of an electrical potential to the fluid, the fluid has enhanced flexibility and multiplicity of purpose over prior art fluids. The conversion table stores dot number data, which represents number of dots to be created in one pixel group, in relation to a combination of a pixel group classification number allocated to each pixel group and the specified pixel group tone value of the pixel group.