The following comes from the Printing HOWTO regarding using the hplip for cups printing and HP printers: "The HPLIP Project embraces the hpijs driver and includes scanner support and service tools for various multi-purpose peripherals. For printing support, you must have the ppds USE flag enabled." Now, if it's required for printing support, which is the whole point of this document, I think it should be made a tad clearer than this small notice before emerge code. Instead, it should probably be added as an <impo> tag after the code: <impo> For printing support, you must have the ppds USE flag enabled! </impo> as such.
Fixed without an extra red box