(1) Field of the Invention
This invention relates to an electronic typewriter for printing text data stored in a memory system on a sheet of paper when printing signals are produced.
(2) Description of the Prior Art
In known electronic typewriters, many of them are capable of printing information on a printing sheet both directly at the time the keys are actuated and after a predetermined time or an arbitrarily selected time has elapsed after the keys are actuated by storing the information in a memory system of a desired capacity. To this end, electronic typewriters known in the art comprise a memory system built therein which includes a read-only memory (hereinafter ROM) which may be a program memory to which a predetermined program is written or a pattern memory for storing patterns of characters and symbols, and a random-access memory (hereinafter RAM) enabling the information written thereto to be replaced by new one. Thus, the electronic typewriters are capable of performing a variety of functions by virtue of the memory system and a central processing unit (hereinafter CPU) for controlling the memory system.
One of these functions is to prepare a text not only by the operation of the electronic typewriters themselves but also by storing in the memory system those data which are transmitted from similar equipment or other external devices to the electronic typewriters, so that the contents of these texts can be printed on a printing sheet when it is necessary to do so.
Electronic typewriters of the prior art of the above-noted construction have suffered some disadvantages. One of them is that when a text carrying data stored in the memory system differs in size from a printing sheet, the operator would experience difficulties in judging whether the contents of the text could all be printed on a single printing sheet or it might become necessary to replace the printing sheet by a new one while printing is in progress. This has often led to the printed sheets being unacceptable in appearance.