Type 1 Scaler uses Type 1 PostScript fonts to draw smooth fonts on the screen in applications that use Apple Type Services for Unicode Imaging (ATSUI). Type 1 Scaler does for ATSUI applications what Adobe Type Manager (ATM) does in traditional QuickDraw applications.
Unless you have an ATSUI enabled application, you can disable the Type 1 Scaler to free up about 1 megabyte of memory.