How to Remove the blog name from a post,page,or archive title in WordPress

How can the blog name be removed from the title of a post,page,or archive without using S.E.O plugins?

The blog name is being appended to the title of a post,page,and archive using the following code from header.php :

<?php wp_head(); ?>

Which creates the title:

Name of Post/Page/Archive/... | Blog name

However, I only want it to display the title like this:

Name of Post/Page/Archive/...