Hacking the HP45

Powder and inkjet printing
ghvanhoosesr
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Re: Hacking the HP45

Post by ghvanhoosesr »

Greetings Dragonator!

I'm having a doozie of a time trying to get this HP45 printhead and controller to work with Inkjet Commander.
I only have the older hardware in front of me; specifically, the HP45 Standalone V3.01 Controller.
From going through the code for both HP45_Standalone V3 and Inkjet Commander, plus comparing HP45_Standalone V3 code with the HP45_Standalone V4 code, it looks as though the V3 software is missing some code to actually trigger printing. (priming still works though) The V3 software does not appear to be set up to interpret any "Trigger" commands from Inkjet Commander.

What signal from Inkjet Commander to the HP45_Standalone V3 software will make the printhead print?
or,
Is there an older version of Inkjet Commander that will work with HP45_Standalone V3 software?
or,
Are there any code segments I can add to the HP45_Standalone V3 software that will make the printhead print?
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dragonator
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Re: Hacking the HP45

Post by dragonator »

There are basically 2 ways the controller currently can print. The first is through an encoder. This is how it was originally designed for Oasis. The controller keeps it's position and when it sees the to be printed image is passing under the printhead in the right direction, it prints the image.

The second way is through virtual motion. This takes an expected speed, and a trigger, software or hardware, to determine a position. After that it handles the actual printing of an image the same. Both ways tell the head that it is moving and printing should happen in the right locations.

The older versions have not been supported for a while, but the virtual motion should be hackable into the older V3.01 controller. From memory, the biggest difference is the lack of the 74HC123 chip, that was needed for DMA printing. Your head should print a bit slower, but should still be able to handle things.

If you have a quadrature encoder you can try hook that up. Inkjet commander might (no guarantees though) work, and this is designed to simply send images and let the user handle the movement of the printhead.

https://github.com/yvodehaas/Inkjet-commander
rofl
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Re: Hacking the HP45

Post by rofl »

dragonator,

I have some questions regarding printing with HP45 using controller version V3.02. Recently I did some tests with regular image printing (not SVG) and I noticed some weird, incorrectly sprayed vertical lines of ink. Here are the images:
Screenshot 2022-11-26 130307.png
Screenshot 2022-11-26 130307.png (502.81 KiB) Viewed 9 times
Screenshot 2022-11-26 114149.png
Screenshot 2022-11-26 114149.png (450.34 KiB) Viewed 9 times
I marked the direction of swipe. It does happen at the beginning and also during the swipe. Sometimes there are multiple mis-jets sometimes there are only single vertical lines. That is really what I do not understand.

Also, perhaps you have experienced with the issue I have outlined in red, where initial sprays produce some foggy/cloudy like areas? It is weird as subsequent lines of swipes produce sharper starting edges of the image as you can see. The ending edges also tend to be relatively sharp. DPI is ~200. Interestingly, new black ink HP45 produce sharp images/edges as you can see, but head with my own ink tends to have this issue. It also seems that the longer pause between each swipe, the more chances of getting this cloudy start. It might be related to the binder liquid it self, perhaps it dries too quickly and that results in some kind of failure to start smoothly, but I do not know for sure now.

Thanks.
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dragonator
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Re: Hacking the HP45

Post by dragonator »

I marked the direction of swipe. It does happen at the beginning and also during the swipe. Sometimes there are multiple mis-jets sometimes there are only single vertical lines. That is really what I do not understand.
There is a known issue that on one side the nozzle table has a few swaps in it. I have had this on my list for a while, but I have not had much time for HP45 related stuff in the last while. This shows itself as lines in the printing direction itself, that clearly are supposed to be printed on a different height.

What your images are showing are lines perpendicular to the printing directions. These are a bit more of a mystery to me. Can you share (either with an image or in text) the command line of the image being sent? I am curious to see if this artifact is sent, or if it comes from the printhead itself. I have not ever seen these lines in my prints.
Also, perhaps you have experienced with the issue I have outlined in red, where initial sprays produce some foggy/cloudy like areas? It is weird as subsequent lines of swipes produce sharper starting edges of the image as you can see. The ending edges also tend to be relatively sharp. DPI is ~200. Interestingly, new black ink HP45 produce sharp images/edges as you can see, but head with my own ink tends to have this issue. It also seems that the longer pause between each swipe, the more chances of getting this cloudy start. It might be related to the binder liquid it self, perhaps it dries too quickly and that results in some kind of failure to start smoothly, but I do not know for sure now.
This issue I have seen before. This to me happens with older heads and heads that have not printed for a while. This is the ink drying in the nozzles. What has worked for me is soaking a rag in isopropyl alcohol and properly cleaning the head with this. For your own ink I do not know what else might help, but for me the issue has mostly been ink drying in the nozzles.
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