US Patent 7800638 Platemaking apparatus

A laser engraving machine has a recording drum 11 rotatable with a flexo sensitive material 10 mounted peripherally thereof, and a recording head 20 movable parallel to the axis of this recording drum 11. The recording head 20 includes a first laser source 21 for emitting a precision engraving beam L1, a second laser source 24 for emitting a coarse engraving beam L2, an AOM 22 for modulating the precision engraving beam L1, an AOD 23 for causing the precision engraving beam L1 to scan axially of the recording drum 11, an AOM 25 for modulating the coarse engraving beam L2, a synthesizing device 27, and an optic 26 for condensing the precision engraving beam L1 and coarse engraving beam L2 synthesized by the synthesizing device 27 on the flexo sensitive material 10.