Does Drawing on Experience Infringe on Other's IP?

Daniel Paull asks: "I recently asked one of our developers to draw up a design for a specific component. After a few hours he returns telling me that he'd solved a very similar problem a previous place of employment and that they had developed a "neat" solution. The developer then became concerned that a ground-up re-implementation of these design patterns and principals may infringe on the other companies intellectual property or breach some copyright laws. This developer is talented and experienced - that's why we hired him. The question is, at what point does 'drawing on experience' cross the line and invade others IP?"