1.  Field of the Invention
This invention relates to the art of printing. 
2.  Brief Description of the Prior Art
The following U.S. patents are made of record: U.S. Pat.  No.  1,098,407 granted Jun. 2, 1914 to Frank C. Roberts; U.S. Pat.  No.  4,776,714 granted Oct. 11, 1988 to Ikuzo Sugiura et al; and U.S. Pat.  No.  4,768,890 granted Sept. 6, 1988 to Kazunosuke Makino. 
Prior art printers such as disclosed in U.S. Pat.  No.  4,776,714 are adapted for printing on wide webs.  The line of printing elements remains stationary and the platen roll rotates while the web of record members advances.  When a wide web of record members is positioned between the printing elements and the platen roll, the printing elements are in printing cooperation with the rotating platen roll.  The printing elements and the platen roll are urged toward each other to provide the proper printing pressure of the printing elements against the web of record members.  The line of printing elements and the contact surface of the platen roll are generally parallel to each other.  It is sometimes desirable to use such a printer, which is adapted to print on a wide web, to print on a narrow web.  In this situation, the printing elements which overhang or extend beyond the side of the narrow web are abraded by the platen roll as the web advances through the printer.  This causes excessive wear on some of the printing elements.  The print head is a particularly expensive printer component.  The platen roll is also abraded, which degrades the platen roll.  Premature wearing out of either the print head or the platen roll causes service problems and/or downtime.