Patent GB-1415986-A (GB)
Title: Teleprinters
IPC: B41J7/36
Filed: 1974-04-03
Abstract: 1415986 Teleprinters SIEMENS AG 3 April 1974 [10 April 1973] 14717/74 Heading H4P A travel summing linkage, for adjusting a type carrier, e.g. of cylindrical pattern, in a teleprinter using an n-element code in which a combination of two code elements characterizes characters which are not to be printed, has a plurality of setting stages in which the ratio between the travel introduced by each stage to that introduced by the preceding stage is two, except that two of the setting stages introduce identical travel values which form the highest setting values of the linkage. The two particular setting stages are assigned to code elements characterizing characters which are not to be printed, in such a way that the two setting stages adopt different setting positions, and means are provided whereby print-out is prevented when said code elements are present. If the teleprinter is designed to print 96 characters, advantageously these will be arranged at the circumference of the type cylinder at six levels each having sixteen type characters disposed one above the other. If the number of characters is 64, then the height of the type cylinder can be reduced to four levels of sixteen type characters each. The associated travel-summing linkage for the rotary setting can be driven to sixteen different positions by the use of information inputs provided by four of the code elements of CCITT No. 5 teleprinter code. The travel-summing linkage for the " lift " setting of the type carrier enables six or four position levels to be set. When using the CCITT No. 5 code, one of the two code elements producing the same setting travel values can be inverted before application to the associated setting stage of the travelsumming linkage. If, for example, the sixth code element is inverted, then the numerals and characters are assigned the short setting travels 1 and 2. By inverting the seventh code element, on the other hand, these same setting travels are assigned to the upper case and lower case letters. The inversion of the sixth code element advantageously assigns the shorter setting travels to the characters which are used most, and thus improves the printing speed. Whether it is advantageous to invert the sixth or the seventh code element depends upon the particular application of the teleprinter. Inversion of seventh code element means that the travel increments 0 and 1 are assigned to the upper case letters and those 4 and 5 to the numerals. This can be of advantage when the teleprinter is being used to print texts because then the most frequently occurring characters are associated with the shortest travels and wear is therefore reduced to a minimum. Conversely, if the teleprinter is mainly to be used in association with a computer then it is advisable to invert the sixth code element because in this way the travel increments 1 and 2 are assigned to the numerals and characters. This most frequent embodiment of the invention has been shown in column 3 of Fig. 1 (not shown). In column 4, the corresponding travel positions are shown as the sum of their individual summing increments. Fig. 2 (also not shown) shows an application of the arrangement to a 64-character printer. Because a 64-character printer only has upper case letters and the information about the differences between upper case and lower case letters is contained in the sixth code element, in this embodiment of the invention the sixth code element is suppressed and the seventh code element has the travel value 2 (column 5). Thus, another advantage of reducing the travel value of the seventh code element is that merely by suppressing the sixth code element, the travel-summing linkage used in the 96-character printer, can also be used in a 64-character printer.