PRE-PROCESSING METHOD IN HYDRAULIC TRANSFER WORKING

PROBLEM TO BE SOLVED: To provide a pre-processing method performed with sufficient coating film adhesion and excellent profitability at the time of hydraulic transfer by using a molding made of polycoarbonate, polypropylene or polystyrene as a body to be transferred. SOLUTION: In the case of transferring a pattern on a surface by supplying a transfer film F in a state of floating the film F on the water surface in a water tank T and pressing down a body W to be transferred from the upside, the surface of the body W to be transferred on a belt conveyer 2 is uniformly irradiated without a shadow with light from a low pressure mercury lamp emitting mainly a ray near to 180 nm and 250 nm in a process before being transferred. As the result, in the case of water pressure-transferring a molding made of polycabonate, polypropylene or polystyrene as the quality of the material, complicated primer coating which is conventionally executed as pre- processing is not necessary a work load can be reduced economically.