Abstract: An automatic envelope stuffing by code reading improvement having code-reading, fiber-optic bundle ends equally spaced longitudinally along a read head, separated the same distance as code marks carried on the paper to be stuffed are separated. Located past those code-reading elements are two control-reading, fiber-optic bundles spaced longitudinally, but relatively close together. A light-source, fiber-optic bundle is located beside each reading bundle. The paper is moved longitudinally, and the apparatus responds to the first mark sensed by the first control-reading elements to read from all of the code-reading elements in parallel, and then to terminate that reading in response to the sensing of the first mark by the second control-reading element. Error from dirt and extraneous marks on the paper is greatly reduced.