How do I sharpen/bold-en a picture in Photoshop CS2 without making it look pixelated?

I have a black and white picture in CS2 that is mostly black lines and curves. After making the image smaller, it looks a little blurry. I tried to restore it in it's smaller size with filter--> sharpen, but the lines and curves look pixelated. How can I properly restore the image in it's new smaller size without making the lines/curves look pixelated?