Post by thread:[EE] DIY inkjet head

Hi! I am trying to find some info on how to build a inkjet head, but I got nothing :( My idea is make a low res (50dpi?) to print direct on the walls. I had seen one made of spray cans, but its just too big. Someone know where can I find some info? Thanks! --------------------------------- Ricardo de Azambuja

On Feb 28, 2009, at 9:05 AM, Ricardo de Azambuja wrote: > I am trying to find some info on how to build a inkjet head, but I got > nothing :( > > My idea is make a low res (50dpi?) to print direct on the walls. I > had seen one made of spray cans, but its just too big. I don't think that the technology used in modern inkjets (piezoelectric, thermal "bubblejet") scales "up" to larger sizes; the physics would seem to be pretty dependent on moving very small bits of ink around. (the HP thinkjet, 1984, was the first consumer (thermal) inkjet printer, and had a resolution of 150x150dpi.) You may want to look at the older "continuous ink jet" technology (used for marking commercial products), but it sounds big, messy, monochrome, and complicated. BillW

As Bill pointed out, the techology used to make modern inkjets depends on the physics of very small droplets. It won't easily scale up to 50dpi. You might look at a cheap airbrush: http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=47791 Figuring out how it works (blowing air across the ink nozzle pulls the ink into the airstrem) might give you some ideas on how you can create very small air-compressor powered, solenoid controlled inkjet heads. If you need it to be small, you might look at little disposable CO2 cartridges rather than the compressor, and scale it down so it uses very little air to paint a dot. Good luck! -Adam On Sat, Feb 28, 2009 at 12:05 PM, Ricardo de Azambuja <spam_OUTricardo.azambujaTakeThisOuTgmail.com> wrote: {Quote hidden}> Hi! > > I am trying to find some info on how to build a inkjet head, but I got > nothing :( > > My idea is make a low res (50dpi?) to print direct on the walls. I > had seen one made of spray cans, but its just too big. > > Someone know where can I find some info? > > > Thanks! > > --------------------------------- > Ricardo de Azambuja > -

> I am trying to find some info on how to build a inkjet head, but I got > nothing :( > > My idea is make a low res (50dpi?) to print direct on the walls. I > had seen one made of spray cans, but its just too big. > > Someone know where can I find some info? 50DPI is dots about 0.5mm. A bit big for normal inkjet printers, but about right for dot matrix. Maybe you can load up a ribbon with a lot of ink, or figure out a way to drip paint over the pins. You can get exactly what you want, Google "product marking" and be astounded by the prices. As a bonus, these systems are often non-contact, and can spray ink about 10mm or so. There's a few different types, one type uses pressure to squirt tiny drops of ink. I'm not exactly sure how that works, apparently solenoids are involved (like dot matrix I suppose). Have a rummage at <http://www.google.com/patents>. You may be able to duplicate that with a hypodermic needle. The tube is too narrow for the ink to flow, and applying a bit of pressure on the syringe will get a tiny ball of ink at the tip (oh, grind the sharp bit off!). Press this against the wall and the drop will transfer. If you release the pressure in the syringe plunger at this point it'll suck the ink back in, and so releases just the drop. A stepper driving a fine pitch threaded rod is needed. Of course for colour you'll need a few of them. Tony

This site/company has more nozzles than you poke a stick at. http://spray.com/ Not sure if they can help with what you want to do but they may have run into a similar operation. >>> On 28 Feb 09 at 12:05, in message <.....463443c60902280905r5ebd7dedl8c87e4a620b60e61KILLspam@spam@mail.gmail.com>, Ricardo de Azambuja <ricardo.azambujaKILLspamgmail.com> wrote: {Quote hidden}> Hi! > > I am trying to find some info on how to build a inkjet head, but I got > nothing :( > > My idea is make a low res (50dpi?) to print direct on the walls. I > had seen one made of spray cans, but its just too big. > > Someone know where can I find some info? > > > Thanks! > > --------------------------------- > Ricardo de Azambuja