Page 1 of 12

Hacking cartridge HP 84/85

Posted: Sat Aug 25, 2018 6:08 pm
by MAsic12345
Hello everyone, I want to hacking cartridge HP 84/85,
I'm from Ukraine, so I do not write clearly
Help me hacking this cartridge
I've already done something but I do not know what signal that means
if something is wrong, then correct me
help connect to arduino thank you
Here is a photo and links
https://www.youtube.com/watch?v=6YCP6Y2Rz5k

Re: Hacking cartridge HP 84/85

Posted: Sun Aug 26, 2018 9:40 am
by MAsic12345
that's how the cartridge looks like xp 84/85

Re: Hacking cartridge HP 84/85

Posted: Mon Aug 27, 2018 4:04 pm
by dragonator
Hello and welcome.

The HP84 you are suggesting seems really interesting. I am afraid hacking it is a bit beyond my skill right now, but I have seen people here who are eay better at it. If I am not too mistaken, the top row of pads (1-4) are used for identifying the printhead and how much ink is left. This part is often hacked with bought printers. For any hacked head, it might not actually be necessary.

What more do you know about this printhead. What DPI is it, and how many nozzles does it have?

Re: Hacking cartridge HP 84/85

Posted: Tue Aug 28, 2018 6:01 am
by MAsic12345
so you're right, these 4 chip contacts, and I will not use it
Tse cartridge 304 nozzles
600 dpi
12 kHz

Re: Hacking cartridge HP 84/85

Posted: Wed Aug 29, 2018 6:03 am
by dragonator
All the specs seem awfully similar to the HP45. I suspect that they used the same hardware (with some added nozzles, which were still possible in the 14x22 grid) and added a driver chip on the printhead. I also suspect that the 9.5V lines may vary a bit while printing. On the HP45 the voltage officially is variable.

I can not instantly derive from the logic analyzer data what pins do what. I do wonder if in 1998, they would already have some advanced controller in the head that does all of the driving itself. Perhaps the way the printer talks is more basic, simply sending the state of all nozzles over something serial/shift register and then controlling the head directly using only a few pins, like it is a HP45 with pin saving electronics attached.

Re: Hacking cartridge HP 84/85

Posted: Thu Aug 30, 2018 6:16 am
by MAsic12345
I also think that the heads are alike, for my 3d printer I will use the printer DesignJet 90r,
in this printer there are 6 colors and 6 separate heads, from which I will use only 5 goals, the 4 main color is , and the fifth - the binding fluid for gypsum
I think that the control of the print head system is the same for each head, since they are identical from one another,and all 6 heads use 304 nozzles each head.

dragonator
How do you think your control board xp 45 can come in order to control xp 84?
for my printer I will not make a new carriage I will use an existing carriage

Re: Hacking cartridge HP 84/85

Posted: Thu Aug 30, 2018 10:45 am
by dragonator
I think you are better off making something else than the HP45 driver. Most of what is in the HP45 driver seems to be there integrated the HP84. If you are lucky all you have to provide to the printhead is power and signals at logic level. You might even be able to just directly hook up a microcontroller to the printhead.

The only real challenge is figuring out how the signals work. What you might do, if you are willing to risk a head or 2, is tape of one contact at a time and see what happens. Perhaps you can derive from that what pins do by looking at what stops working. Also you can try printing a big black circle, or a square at 45 degrees, to see how this affects the data sent to the head. There have to be clock signals and data signals, and perhaps some synchronization signals connected to an encoder (channel 8 looks like that, but that is just a hunch right now)

Re: Hacking cartridge HP 84/85

Posted: Thu Aug 30, 2018 6:11 pm
by MAsic12345
Here is the result when typing a circle.
is tape of one contact at a time and see what happens. Perhaps you can derive from that what pins do by looking at what stops working.
if I am damaging one contact then how can I find out what is specifically damaged?

Re: Hacking cartridge HP 84/85

Posted: Sat Sep 01, 2018 8:18 am
by dragonator
With the HP45 you can clearly see patches of ink stopping when you disable some pads. With some time you can already get a good idea of which pad does which area of nozzle. With your printhead it might be a bit more problematic, there are not that many pads that really do anything, so disabling any pad might just stop it printing completely. The only thing you might find is how many data pins there are. If you tape of channel 1, 4, 8 or 13, you might get half the head stopping, and half continuing, but that is no guarantee.

By the looks of it 4 and 8 handle data, while 1 and 13 look like clock pins. What 9 and 10 are doing is a bit of a mystery to me. That is my guess though, I do not have the most experience with serial protocols.

Is the logic analyzer graph from you printing the entire picture or just part of it?

Re: Hacking cartridge HP 84/85

Posted: Sat Sep 01, 2018 7:17 pm
by MAsic12345
I tried to change the analyzer program because the previous bug
and got more accurate data,
oscillogram 5 seconds in the middle of printing, it is clearly visible when the carriage passes and produces ink
I think that on these wires 8 \ 10 \ 11 \ 17-18, where there is no signal, it is a constant voltage to include a head
9 \ 13, as you say data for injectors,and they are 5 \ 14 \ 16 \ 19 I do not know what they mean
I would like to connect arduino and try but need to know where the spray nozzles are heated