Ink jet print head:  does orientation matter? - Page 1
Forum section: electronics / projects

author: mark03
author_rank: Frequent Contributor
timestamp: November 17, 2016, 06:03:14 am
content: I'd like to build a polargraph--a sort of plotter with a hanging carriage/pen supported and positioned by two motors in the upper corners of the canvas. The canvas is mostly vertical, but tilted back far enough so gravity keeps the carriage in contact with the paper. See e.g.All of the polargraphs I've seen use a pen of some sort. I thought it might be interesting to try an ink jet head instead. Hardware hackers have figured out how to interface with some of the older/simpler ones, e.g. InkShield with the HP C6602 (http://nicholasclewis.com/projects/inkshield/). Does anyone know if it would make a difference, printing to a vertical surface? And how prone they are to clogging?A robust single-nozzle ink jet would be ideal, of course, but AFAIK nobody has figured out how to fabricate one in the home lab. There have been experiments using piezo benders with 3-D printed ink chambers, with limited success.

author: mark03
author_rank: Frequent Contributor
timestamp: November 28, 2016, 05:37:42 am
content: Was hoping there might be at least one ink-jet expert in the room. Anyone know if it's safe to take my regular ink-jet printer and turn it vertical as a test?

author: IanB
author_rank: Super Contributor
timestamp: November 28, 2016, 06:27:31 am
content: I'm not an expert, but I have observations.Ink jet heads dry out and clog up as sure as night follows day.When installed in a printer they are parked against some kind of seal to keep the air way from them. Also, before every use they go through some kind of cleaning cycle that involves spraying ink forcefully through all the nozzles into an ink trap to clear the dried ink away.If you took a print head out of a printer and suspended it in free air without all of these mechanisms it would rapidly become non-functional.

author: DimitriP
author_rank: Super Contributor
timestamp: November 28, 2016, 07:42:50 am
content: I wouldn' call myself an expert either, but I've had cartridges go dry, and heads clogg and replaced.What he said ^^^ . The good news is the C6602 cartridge hs the printhead "built-in".If you did work out how to use it, the cartridge could be removed and stored in a small airtight container.With the combo packs HP usually includes a holder for when changing from the text color to the photo color ink.So in the case of the 6602, worse case if it dries out for around 26 bucks you are back in business.Printing upside down would probably work as long as this is not the resting place of the head.

author: RoGeorge
author_rank: Super Contributor
timestamp: November 28, 2016, 07:57:25 am
content: Quote from: mark03 on November 17, 2016, 06:03:14 amAFAIK it should work on a vertical surface but is far from certain. Anyway, you need to park the heads sealed when they are not printing. This is exactly what the printer is doing when it is not printing. Also, from time to time and before each use, the printer will purge some ink to avoid nozzle clogging. There is a small vacuum pump outside the printing head that is doing just that.Quote from: mark03 on November 28, 2016, 05:37:42 amNot safe.- Inkjet printers have a tank for purged (wasted). If that tank is full and you turn your whole printer vertically, the wasted ink tank might spill inside the printer.- Depending on the printer model, the printer head use gravity in order to keep the printing heads on top of a guiding rod. If you change the orientation, the printer head might flip and knock to the printer case or other parts.You may want to download and read some service manuals from a few inkjet printers in order to understand how did they work before proceeding to your project.Good luck!

author: amyk
author_rank: Super Contributor
timestamp: November 28, 2016, 08:57:03 am
content: Piezo printheads can fireupwardsand will generate enough suction (as long as they've been purged of air) to lift ink a few inches. They are less prone to drying in humid climates e.g. southeast Asia.

author: mark03
author_rank: Frequent Contributor
timestamp: November 28, 2016, 06:03:39 pm
content: Can a hobbyist actually acquire a  piezo printhead? I had the impression all of the consumer printers are using thermal ink-jet.Is the ink an aqueous solution? What if I just park the "gondola" (the suspended part of the polargraph) on top of a wet towel when not in use?It would be really nice to have a more robust, single-nozzle jet--something much fatter (lower resolution) than what you find in consumer printers, and easier to clean/unclog. But I don't have the mechanical skills or the time to embark on such a project.

author: amyk
author_rank: Super Contributor
timestamp: November 29, 2016, 04:10:49 am
content: Quote from: mark03 on November 28, 2016, 06:03:39 pmEpsons at least were piezo several years ago, still seem to be now. There are a bunch of peopleheretalking about Xaar commercial piezo heads, which are not cheap but probably quite reliable.More references on how to drive Epson piezo heads can be found in patents and the following:https://dspace.mit.edu/bitstream/handle/1721.1/85435/870681346-MIT.pdf?sequence=2http://www.piclist.com/techref/pcb/etch/custom-vs.htmQuote...it depends on what ink you use. A wet towel would not be a good idea, since it would just wick out all the ink. What you really want is a sealing cap.Quote"much fatter"... how about a solenoid and a can of spray paint?

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 29, 2016, 06:01:56 am
content: Quote from: amyk on November 29, 2016, 04:10:49 amyour post is locked thank you.

author: tooki
author_rank: Super Contributor
timestamp: November 30, 2016, 03:25:28 pm
content: Quote from: mark03 on November 28, 2016, 05:37:42 amI would be leery of using a whole printer in a different orientation, for the reasons others have already enumerated. (As an aside, I love the technical word for the thing where waste ink is dispensed, whether it uses a sponge or a funnel to a tank: the spittoon!)The heads themselves, however, don't care. Large-format inkjet printers (like the kind used to print 20 foot wide banners) routinely use heads vertically.