Hi All,
Just an idea to throw out there, perhaps plant a seed with someone.
Many years ago (1988) there came out a range of Tektronix Phaser printers (Xerox took over the line and they also sell laser printers under the same name). These came out at a time when high-speed true colour lasers and inkjets were rare and are still used for proof printing and other niche markets. They were CMYK solid wax printers and had an industrial grade print head that can last up to a million pages (the black in was free but power cycling used a bit of the colours as well).
[en.wikipedia.org]
Basic function was a 4 colour page (210mm) wide print head with nozzles every 5mm across or so (about 42 for each colour) This print head would move across only 5mm during a page print. The printed image was sprayed (piezo pumps) onto a heated smooth (silicone oil wiped) drum that had a circumference of page height (about 300mm). It would print one line from each nozzle (all colours) around the drum and then step over a bit and do the next line, repeat 60 (guess) times to cover the 5mm nozzle spacing and cover the whole drum. The still soft image was then offset against a sheet of paper in one turn and it would set instantly and the drum was wiped clean with a (silicon) oily felt. All this was pretty quick and the quality was pretty good with vibrant wax.
Now the issue, this nozzle has to print horizontally (usually onto the drum because it has galleries with molten ink that is automatically topped up as it is consumed by melting drop by drop from solid blocks (they look and work like jumbo wax crayons, the black ones were free). The head is likely very expensive to make but in quantities could be affordable. or availbale as a spare part. Moving a build platform up and down in front of the standard heads might be possible to test the technology.
What if one had a regular wax and a water soluble poly vinyl alcohol in just two sets of jets. Arrange it so the openings point down. Print one layer at a time in wax and support (with voids where savings would make sense as only the wax and PValcohol shells are needed) on a bed that moves in one axis and the head moves across slowly from side to side to cover the jet spacing.
Dissolve the support and you have an investment casting pattern that is limited in size by your head width.
Working with a puddle of molten wax and a piezo head may initially scare people from experimenting but it has all be done so it is possible. Piezo heads can be arranged in arrays and gaps between the jets is not a problem as one can scan across to cover the spaces
As an aside I recall there was a range of IBM mainframe colour inkjet printers [Canon Colour Ink Jet printers. Model PJ-1080A. OEM by IBM for mainframe terminals] that has a single jet per colour and were low resolution (60/72 dpi) like early dot matrix printers, I remember a biology lab dude once purchased a few I had picked up to use the piezo pumps for spraying samples onto electrophoresis or chromatography substrates or something like that, this was 15 to 20 years ago.
Kalle
--
Johannesburg, South Africa
Just an idea to throw out there, perhaps plant a seed with someone.
Many years ago (1988) there came out a range of Tektronix Phaser printers (Xerox took over the line and they also sell laser printers under the same name). These came out at a time when high-speed true colour lasers and inkjets were rare and are still used for proof printing and other niche markets. They were CMYK solid wax printers and had an industrial grade print head that can last up to a million pages (the black in was free but power cycling used a bit of the colours as well).
[en.wikipedia.org]
Basic function was a 4 colour page (210mm) wide print head with nozzles every 5mm across or so (about 42 for each colour) This print head would move across only 5mm during a page print. The printed image was sprayed (piezo pumps) onto a heated smooth (silicone oil wiped) drum that had a circumference of page height (about 300mm). It would print one line from each nozzle (all colours) around the drum and then step over a bit and do the next line, repeat 60 (guess) times to cover the 5mm nozzle spacing and cover the whole drum. The still soft image was then offset against a sheet of paper in one turn and it would set instantly and the drum was wiped clean with a (silicon) oily felt. All this was pretty quick and the quality was pretty good with vibrant wax.
Now the issue, this nozzle has to print horizontally (usually onto the drum because it has galleries with molten ink that is automatically topped up as it is consumed by melting drop by drop from solid blocks (they look and work like jumbo wax crayons, the black ones were free). The head is likely very expensive to make but in quantities could be affordable. or availbale as a spare part. Moving a build platform up and down in front of the standard heads might be possible to test the technology.
What if one had a regular wax and a water soluble poly vinyl alcohol in just two sets of jets. Arrange it so the openings point down. Print one layer at a time in wax and support (with voids where savings would make sense as only the wax and PValcohol shells are needed) on a bed that moves in one axis and the head moves across slowly from side to side to cover the jet spacing.
Dissolve the support and you have an investment casting pattern that is limited in size by your head width.
Working with a puddle of molten wax and a piezo head may initially scare people from experimenting but it has all be done so it is possible. Piezo heads can be arranged in arrays and gaps between the jets is not a problem as one can scan across to cover the spaces
As an aside I recall there was a range of IBM mainframe colour inkjet printers [Canon Colour Ink Jet printers. Model PJ-1080A. OEM by IBM for mainframe terminals] that has a single jet per colour and were low resolution (60/72 dpi) like early dot matrix printers, I remember a biology lab dude once purchased a few I had picked up to use the piezo pumps for spraying samples onto electrophoresis or chromatography substrates or something like that, this was 15 to 20 years ago.
Kalle
--
Johannesburg, South Africa