Hacking a HP #20/#49 head

Powder and inkjet printing
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nighthunter
Posts: 1
Joined: Fri Dec 01, 2023 11:19 pm

Hacking a HP #20/#49 head

Post by nighthunter »

Hi friends,
i am trying to make use of HP 20 and 49 heads as they are only dumb resistors in the cartridge, but i looked at the waveform that drives the nozzles, Vpp seems to be around 16V (Primitive resistance is aroud 33R), but it seems that for every nozzle from one color (or better say union as they are 6 groups of nozzles) there is a weaker pulse about 6-7V and one main pulse probably for firing. I want to ask why there is such a behavior it is just to balance the vacuum generated by the actually firing nozzle to restrict sucking air from the not operated nozzles? Pulse duration is for every pulse weak or full about 2.5us. Did someone encountered this behavior?
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