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To: I1002812--IBMMAIL NFB R&D Committee
FROM: Steve Jacobson - IT Sales & Marketing Systems
3M Company - 555-01-03 Phone: (612) 733-9780
St. Paul, MN 55144 FAX: (612) 736-6037
Subject: Braille Plotters
After reading the many interesting ideas expressed here, I thought maybe
I'd do something that might be dangerous, get practical. Although we
started this discussion from the viewpoint of our attempts to produce
braille output from a graphic calculator, the problems of raised line
images go far beyond that. In particular, maps, floor plans and
electrical circuits come to mind.
The spur wheel approach has several limitations in this regard. First,
it can't create lines of varying dot spacing as might be required for
the reproduction of maps. If the paper positioning mechanism is very
accurate, some variation in texture might be accomplished by multiple
passes. Also, I don't see how the spur wheel method could be used to
place even simple braille labels on a drawing. It could still be useful
if it could be manufactured and sold at a low enough price. However, it
would have to be controlled in the X-Y plain, be raised and lowered, and
be rotated to keep the wheel oriented to its direction of motion.
Although this could certainly be done, it doesn't sound like any
existing device, so I doubt the price would be low.
Now the vibrating pin, or "power stylus" as I called it earlier. This
approach would get around the limitations above. One could vary the dot
pitch and probably produce braille labels on drawings. The orientation
of the vibrating would not be a problem. However, several persons have
raised a valid point that there could well be maintenance problems. Not
insignificant is the very slow speed, especially at closer dot spacing.
If we found that we had to move both a dot producing and a dot forming
element on oposites of the page, the unit would become larger and more
expensive to build. In the end, this approach would also be expensive.
The dot matrix printer approach was interesting. However, none of the
dot matrix printers that I have seen use any kind of easily replaceable
platten behind the print head, although I haven't seen that many. Those
I have had the pleasure of unjamming usually have a thick metal strip
that absorbs the force of the print head. Even if the print head
produced enough force to create a raised image, it would not be a simple
matter to substitute a rubber absorbing material for the metal strip.
my conclusion is that there are three directions that will lead to
higher detail drawings. They are seeking out or modifying an existing
medium or high speed braille printer, exploring encapsulated paper
approaches further, and examinating the bubble-jet technology.
The advantage of having a braille printer that could both do higher
detail graphics and print braille text is that the add-ons should be
cheaper. I believe the Romeo printer had a continuous dot forming groove
that could possibly be used for higher detail graphics depending on the
stepper motors and control circuits, of course. Speed and noise would
still be a problem, though, but that is generally a problem with braille
Encapsulated paper is promising, but the paper is expensive. Perhaps
Robert has the specifications of the device he is using and can provide
the maximum height of a line or dot, but it looked very good to me. One
could by a laser printer for $600 and one of the infrared devices for
$900 and probably have a raised image system that would be cheaper than
almost any dedicated device we could build. In addition, one would have
a laser printer for text. If there was a way to get the paper cheaper,
$1 per sheet was quoted to me, we could concentrate on the software to
produce the necessary print images.
Finally, what about bubblejet technology? My understanding is that the
Cannon Bubblejet printers use heated ink. Is there some means by which a
relatively inexpensive Cannon printer could produce images in a fashion
similar to the Howe-tech with the right ink?
It just seems to me that these three areas would more likely yield
something useable than would designing something from scratch. As
always, my intention is to stimulate discussion, and I am most
interested to hear how my logic is flawed and what others think.
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