As an author, you are also a copyright holder! It's important for you to know what rights you control for your work, and consider what rights publishers might need before signing any publishing agreements. Many publishing agreements require a complete transfer of copyright from you to the publisher, which means that you no longer have the ability to use your own work without permission.
The copyrights for employees and students of Arizona State University, particularly employees, are affected by the Arizona Board of Regent's (ABOR) Intellectual Property Policy 6-908 (pdf). In general, this policy states that ABOR claims the rights to any intellectual property that is created by an employee in fulfilling their job responsibilities as a Work for Hire (pdf) under U.S. Copyright Law, with the following exceptions:
Additionally, you should be aware of how copyright affects your own research. Any time your research or writing activities involve making copies of, distributing, performing or displaying a copyrighted work, or making a new work derived from an existing one, your actions overlap the exclusive rights granted to copyright holders. You may still be able to do those things (such as under a Fair Use exception), but you should be aware of your own rights and responsibilities under copyright.
Some Common Issues from the University of Minnesota Libraries, describes how copyright considerations affect many common situations that occur when doing research.
According to the law, copyright is granted to authors upon expressing their ideas in a "tangible form", even if it is an unpublished manuscript; no registration is needed to become the legitimate copyright holder of your own work. As the author, you have the exclusive right to copy, distribute or perform your work, unless you give your permission to others to do so. In fact, in order to publish your article, all the publisher needs is your permission, yet standard publisher agreements transfer all your rights to the publisher. You don't have to accept it, as the owner of your own intellectual property.
ASU Library, together with a contract specialist, offer you a toolkit to negotiate with your publisher and retain some of your rights. The Negotiating Guide takes you step by step through a typical negotiating process using clear, everyday language.