Ladder-shaped belt

[Tony Duell]

> 
> 
> On Sat, 2008-01-26 at 22:13 +0000, Tony Duell wrote:
> 
> > The drive belt fro an HP9871 (daiswheel printer, the belt is about 2m 
> > long and looks like a ladder. I am told none have survived. This is one 
> > printer I would love to find, just to see if I can work out some alternative)
> 
> I'm guessing that the rungs of the ladder go between teeth on the
> pulleys, and the rails of the ladder keep the belt in place?  In which

I beleive that is the case. I've never actually seen the HP9871, but I've 
read the service manaul (excellent) on hpmuseum.net.

The first thing to realise is that the mechanism is strange. It's a 
daisywheel printer, and the unusual it is that the motor that moves the 
carriage and the motor that spins the daisywheel are both on the main 
chassis (normally the daisywheel motor is on the carriage, of course). 
They both operate this (the same) toothed belt, somehow one motor moves 
the carriage, the other spins the daisywheel.

I suspect mechanical positioning is somewhat critical!

> case, I'd get the closest matching toothed belt I could find and fit
> little metal end cheeks on the pulleys to stop it sliding sideways.  If
> you were tight for space, you could probably get away with only one
> pulley.

That's basically what I was thinking of doing, given that I could always 
make new sprockets if necessary.

I'd still like to see one of the printers (I do have the interface for it 
to the HP9830, the interface on the printer end is 8 bit parallel, fairly 
Centronics-like). One did turn up on E-bay last year, but even surface 
mail shipping to England was too expensive so I didn't bid.

-tony