Hacking the HP45

Powder and inkjet printing
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Re: Hacking the HP45

Post by math »

Hi Dragonator,

I found this IC that seems more suitable to power the primitive lines:


Is from Allegro and is said discontinued but is largely available (in aliexpress, for sure)
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Re: Hacking the HP45

Post by rofl »

Yvo, glad you started working on controller v4. Really looking forward.

Perhaps you remember me, we talked via email regarding encoder tape I had, which was of wrong resolution and thus head was not printing. I finally managed to get correct encoder tape and I though I will move discussion here as it is more general question now and would be beneficial to others.

When I changed that encoder tape, printing now happens, but I am not sure if I missed something, but I noticed that sometimes when sweep is made, it is not completed entirely, i.e. if we have, let's say, filled circle, and we divide it into three swipes, two of them might be done properly, but one, can be finished like half-way. I assume this has to do something with settings and/or limitations. Could you explain this? I attached image as a sample.
circle.png (2.96 KiB) Viewed 492 times
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Re: Hacking the HP45

Post by dragonator »

I have put the UDN2987 on my list of considerations. It has a latch, can handle the voltages and does seem to be (barely) fast enough. The discontinued status and max 1000ns response time do worry me a bit though. Once I am certain that the TLC59213 is indeed the bottleneck I will see if this chip is indeed a working solution.

You are using Oasis controller software to drive you system? Can you look at buffer write left or read left before you start moving? You can try lowering the resolution to see if that helps. Can you show what is being sent to the printhead? This allows me to see if the right data was at least sent.
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Re: Hacking the HP45

Post by math »

As I said, although it is discontinued, Digikey has 8k in stock (and there are many other suppliers). And typical time of response on/off is 100 ns. And it supplies 350 ma in all 8 outputs in a 30% dutty cycle. Supposing a dutty cycle of 8 us ( address on, 3 us, primitive on/off 2 us, address off 3us) we have a dutty cycle of 25% on primitives. Seem to me that this can resolve your problem with tlc59213.
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