Chuck wrote:
The terminal consisted of a leadscrew-fed printing
head with a vertical typewheel rotating
perpendicular to the (tractor-feed) paper. Said typewheel was in contact with an
ink-soaked felt
wheel. Carriage return was accomplished via a large spring. Utter steampunk
simplicity.
This alphanumeric printer was an extension of the printer internally developed by Friden
for its first line of printing electronic calculators, the Friden 115x series.
See my online exhibit for one of the 115x calculators, the 1152 at
https://oldcalculatormuseum.com/friden1152.html
These kind of sucked because of there actually was an intermediate "print wheel
inker" drum between the ink-soaked cartridge-loaded ink-source, and the wheel. This
intermediate wheel was made of a rubber compound that both A) degraded due to solvent in
the ink, and B) degraded due to rubber's usual degradation due to ozone in the
atmosphere. In time, this intermediate roller turned into a wad of black, sticky goo that
clogged up the works of the printer. I have a number of Friden 115x calculators where
this has happened, and replacing that roller is not easy to do, as it's a very precise
diameter. I am pretty sure that the alphanumeric version of this printer (which
Singer/Friden also sold to OEM customers...not sure if they had many takers) had the same
intermediate drum that acted to transfer the ink from the ink roll to the print wheel.
In theory, it was kind of a neat design. In practice, it sucked. One thing that was
interesting is that the characters on the print wheel were organized in a helical form to
help offset the fact that that the carriage motion was constant (it didn't stop when
the hammer was fired). The print wheel for an alphanumeric version was larger in
diameter to allow for the extra characters beyond those used in a printing calculator.