DEC Letterprinter 100 -- what are they selling for?

Tony Duell ard at p850ug1.demon.co.uk
Mon Nov 24 12:41:54 CST 2008



> >It's a 9 pin dot-matrix head which is tilted mechanically (a pair of 
> >solenoids shuttling a shaped core to and fro inside the carriage) to give 
> >18 pin resolution in 2 passes. I find them interesting because of that 
> >curious mechanism.

[...]

> 
> I have two LA100ro as they proved in the field to be rugged and I got to 
> see that from the point of view of DEC printers engineering.  The curious
> approach to "18pin" printing was twofold.  One was to allow fast draft 
> quality printing and the other was rugged high quality printing that could 
> still punch multipart forms with a known reliable head.  At that time there
> were a few 18 pin heads but they didn't have the long term life at sustained
> high print rates.  Note, this is a 1984-5 design so understand that many 
> printers at that time were of smaller or less rugged style or really 
> imposing printers. 

Sure. The idea of using multiple pases to increase resolution was quite 
common at the time. Sanders Associates made a range of 7 pin printers 
with an accurate paper feed mechanism which did 8 pases for some fonts, 
and the result looked as good as and daisywheel I've ever seen. But the 
DEC trick of shifting the printhead vertically I think was unique to the 
LA100 printer, and it's interesting to me for that reason.

But as I've said many times before, I like unusual/curious designs 
whether they're processors or not. So the LA100 printer (and indeed the 
Sanders models I've just mentioned, which have some interesting 
electronics) are things that I am glad to have in the collection.

-tony




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