Hacking the HP45

Powder and inkjet printing
acastel
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Location: Brazil

Re: Hacking the HP45

Post by acastel »

math wrote: Sun Nov 22, 2020 7:52 pm I'm looking forward to seeing your 10V tests on the primitives!
I guess it will not work if you keep the primitive pulse in 1.875us.
math
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Joined: Tue May 24, 2016 1:08 am

Re: Hacking the HP45

Post by math »

Probably not! I have a book of Matt Gilliland, "Inkjet Applications" (2005), with foreword by Frank Cloutier, "Chief Technology Officer for HP's Imaging & Printing Group", what seems to me that author know what is saiyng.
This book treat of hp 51604A cartridge, a 12 nozzles. While this is a diferente cartridge, compared to HP 45, the principles of firing is the same, in the resistor plane of each nozzle.
In the chapter 1, "Firing guidelines", the author affirm: "According to the 51604's data sheet, in order to deliver the proper amount of energy to the 65 ohm resistor, the firing voltage should be no less than 21.0V, nor more then 24.0V dc. Within this range,the pulse width should vary between 4.5 and 6.0 microseconds. Realize that it is the overall firing energy that's critical - not the voltage or amperage. According to HP the optimum firing "energy" is 40 microjoules".
So, at my understanding, there are some compromises among voltages, currents and times of firing the nozzles.
The only constant is the "energy" and there are a interval of voltage respect each cartridge, taking in consideration resistor value of each nozzle.
Taking in consideration voltage measures in real printer, made by you, seems to me that 10V can be in the acceptable range, since the time could be ajustable to more than 1.875us
Farzin
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Joined: Wed Dec 02, 2020 5:35 pm

Re: Hacking the HP45

Post by Farzin »

Dear Friends,

We are working in a Hp45 printer. I used 2 TLC for the primitive with 12 volt and 2 us pulse width.
Here is my sample print with 12 mm height (full odd nozzle).
I think for places that need to all nozzle fire, there is a problems. It is show in a box in my picture.

I would be hear your opinions.
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sample1.jpg
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dragonator
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Re: Hacking the HP45

Post by dragonator »

Hello and welcome,

From what you write I will assume that you wrote the code that fires the nozzles yourself?

Your printing already looks good. The problem you describe sounds very familiar. It is the problem I also have with my heads. For some reason I cannot fire all primitives on an address at the same time. At this point in time I do not have a clean solution, only a workaround.

On each address, do not fire all primitives at once. Fire 5, then 5 more, and then the other 4. You do not need a significant waiting time between firing each set, only enough to be certain the power has stopped flowing to the primitives (500ns or so). If you do this I expect the problems you show to disappear.
Farzin
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Joined: Wed Dec 02, 2020 5:35 pm

Re: Hacking the HP45

Post by Farzin »

Dear Admin,

Yes, i used my code for printing.I used STM32F107 and for coding keil.

I am going to work with a cartridge with height more that 1/2 inch. and now i am search for it.
I would be glad if anyone help me for this.
Regards
Bruno
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Joined: Thu Dec 10, 2020 9:20 pm

Re: Hacking the HP45

Post by Bruno »

Greetings, everyone.

I'm trying to map the pins of a 8-digit chip from an old HP printer. I'm not sure about the contents of the C8855 documentation, but perhaps it can be of some use. Could you e-mail it to me, Dragonator?

Keep up the good work!
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dragonator
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Re: Hacking the HP45

Post by dragonator »

Sent per email. Hope it helps
mobi
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Joined: Wed Jan 06, 2021 10:44 am

Re: Hacking the HP45

Post by mobi »

Hy to all,

Dear Admin please send me the C8855 documentation ?
tomhot
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Joined: Sat Nov 07, 2020 6:51 pm

Re: Hacking the HP45

Post by tomhot »

Excellent instruction! Hi Dragonator, could you email me the C8855 manual as well? Thanks.
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