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Thermal printing fax machines and 1728.

Posted: Fri Jun 18, 2021 8:51 pm
by Boustrophedon
Just watched an old "Secret Life of the Office" video by Tim Hunkin about the fax machine. Early ones, he explained, were thermal printers and had 1728 little heating elements across the width of the page.

Of course I immediately spotted that 1728 = 12^3, which seems an odd weird choice of number, it's not a binary power of 2, but cannot be a coincidence.

Does anyone know why that number?

Re: Thermal printing fax machines and 1728.

Posted: Fri Jun 18, 2021 9:20 pm
by Gfamily
Boustrophedon wrote:
Fri Jun 18, 2021 8:51 pm
Just watched an old "Secret Life of the Office" video by Tim Hunkin about the fax machine. Early ones, he explained, were thermal printers and had 1728 little heating elements across the width of the page.

Of course I immediately spotted that 1728 = 12^3, which seems an odd weird choice of number, it's not a binary power of 2, but cannot be a coincidence.

Does anyone know why that number?
I'd say a credible explanation is that the scan/print heads use 8 pixels per mm, and foolscap paper (often used in USA) is 216mm wide.
It being 12^3 is a coincidence.

Re: Thermal printing fax machines and 1728.

Posted: Fri Jun 18, 2021 9:46 pm
by Woodchopper
Gfamily wrote:
Fri Jun 18, 2021 9:20 pm
Boustrophedon wrote:
Fri Jun 18, 2021 8:51 pm
Just watched an old "Secret Life of the Office" video by Tim Hunkin about the fax machine. Early ones, he explained, were thermal printers and had 1728 little heating elements across the width of the page.

Of course I immediately spotted that 1728 = 12^3, which seems an odd weird choice of number, it's not a binary power of 2, but cannot be a coincidence.

Does anyone know why that number?
I'd say a credible explanation is that the scan/print heads use 8 pixels per mm, and foolscap paper (often used in USA) is 216mm wide.
It being 12^3 is a coincidence.
Looks like that’s correct: https://electronics.howstuffworks.com/g ... chine2.htm