Packaging meant to emulate a brand’s design without using its logo can be a violation of copyright laws. HP actually won a federal court case in March against a Chinese manufacturing company called Ejet, which HP accused of infringing upon its “trade dress,” the technical term for packaging design.

The linked court case says nothing about copyright. And as far as I can tell, 'trade dress' protection isn't rooted in copyright law at all. IANAL.