Halfspace control system for electronic typewriter with correction register

摘要

An electronic typewriter comprising keys 12a and an electronic control system 26 for causing a print wheel 16 to print corresponding characters at successive horizontal positions. A register 86B stores and continuously updates its storage of the last plurality of characters printed. When an error is made, the typist can backspace to the error, automatically recall the incorrect character from the register and erase it by restriking that character via a correction ribbon 28. Actuating a halfspace mode key 24 advances the print wheel's horizontal position by one-half the ordinary space, thereby moving out of normal registration to permit inserting extra characters. Upon such actuation of the halfspace key, the register's contents are cleared so that characters entered in normal registration cannot be used while the print wheel is in an offset location. Characters typed while in halfspace mode are stored in the usual manner. When return to normal registration is desired, the halfspace key is released, again advancing the print wheel's horizontal position by one-half space. Upon such return, the register's contents are again cleared to preclude any non-correspondence between the position of characters taken from the correction register and current registration of the print wheel.