The maker of Splenda, the nation’s best-selling sugar substitute, is demanding an injunction against the manufacturer of a generic version of its product, claiming that consumers are likely to be confused by its use of “virtually identical” packaging that mimics Splenda’s color scheme, graphics and package sizes.

But lawyers for Heartland Sweeteners insist that confusion isn’t likely since its packages always include the logo of the supermarket in which they’re sold. Consumers, they argue, are “well acquainted” with the difference between brand-name products and the cheaper, store-brand products.