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Hmm. interesting idea. I have no long-term measurement yet. Line 9 looks quite similar to what is happening on one 13 though, only with lower voltage… .
Alright, so we are missing 17 which looks pretty much exactly like 10 and 16 and the others. 18, 19, and 20 are GND. 21, 22, and 23 carry 32V when needed, but since I do not have a voltage divider, I didn’t measure that. For line 24, I don’t know. It’s a wide line, so it carries some higher wattage. I’ll have to scope that again before using the logic analyses. I may well be logic GND.
Next block, lines 9 to 16 (00 to 07 in the screen shots). 10 and 16 exhibit the same three-level behavior as 4, 5, 7, and 8. None of them seem to carry any data besides the occasional sync.
9 seems to carry a lot of noise. It does not look like a true signal to me. It could be in trig-state mode with cross talk??
13 seems to be a short sync, but also seems to carry true data around the line 10/11 sync.
12, 14, and 15 are quite busy. 12 runs at about 6kHz, 14 at 300kHz, and 15 at 24kHz.
11 is a slow sync, going to 0V every 1.6 seconds.
On the logic side in a higher frequency, we can see a litte bit more:
OK, so let’s look at some wave forms. In the middle of printing a page of black-only text, I trace the signals for 10 seconds. The first image shows pin 1 to 8 (named 00 to 07 in the software). Pin 4, 5, 7, and 8 show a short spike every 1.5 secs. More on that later. Channel 5 shows blocks of pulses.
Now for a close-up on pin 4. The signal sits at 1.5V, is then pulled down for 12ms, then bounces to 3V for a very short time, and goes back to 1.5V.
Now for pin 6. This looks like a 0-3V clock signal at 66kHz. It comes in 5 or so bursts per Pin 4, 5, 7, 8 cycle. Printing a single line takes less than 1.5 seconds. It seems that instead one burst corresponds to one printed line.
Well, it’s important to use the right tool for the job. Using my new Saleae, I found out MUCH more about the signals. The first finding is, that using a cheap scope will generate false signals and waste of time 😉
All signals are taken at the ribbon cable that leads right to the head, after any electronics. Here is a photograph of how the pins are mapped to head. Note that I defined the leftmost pin as 1. The printhead contacts are of course reversed, so the top right contact is 1 in my previous numbering. All further numbers refer to the ribbon wires!
NOTE: I did flip a few pins in the list above! 18, 19, and 20 are GND, 21, 22, and 23 run 32 Volts. As for 24, I do not know, but it may be 32V as well. That pin only leads to the black cartridge.
I also found a few articles on “band gap voltage generation”, which is a method to generate a temperature independent voltage at precisely 1.25V. One of the pins looks like it is a reference for the 32V lines to keep the print quality perfect (stab in the dark 😉
Lastly, after reading many patents, there is likely an ID chip on the ink head that is read by the printer, as well as temperature sensors. So there are likely lines that transfer data from the head to the controller.
Looks great! This is perfect for simply mounting the head on a motion axis.
Does the CIS have a name or order number? I could not find it on the ‘net.
Some of the signals on the head confuse me. I really don’t know what the 1v +-0.5V signal levels are good for. I have not seen that on other devices before and I don;t see the advantage over the 3V signals. OTOH, I have purposefully not printed with any of the four photo cartridges. Maybe these levels are just some idle noise and pin 11 to 15 are the shift register for the large black tank?!
OK, I had a chance to connect the scope. Careful though: my printer generates no color – one of the 32V lines may be bust. Measure before you connect a logic analyser yourself. Don;t rely on my measurements.
Pin / All black text 1, 2 0V (GND?) 3 0V while idle, const 5V while printing (head electronics power?) 4 0V, const 1.5V while printing (1.5V reference?) 5 0V, 1.5V few long pulses 6 0V, 3.5V, pulses 1us long 7, 8 0V, 30s sine wave around 1.5V (+-0.5V) 9, 10 0V, 1.5V with sine wave disturbances at 60us 11 0V, 3V, slow pulses 12 0V, 3V, pulses around 10us 13 0V, 3V, pulses around 100s 14 0V, 3V, clocks at 3us 15 0V, 3V, pulses between 10ns and 1us 16, 17 0V, 1.5V +-0.5V pulsed, sine wave (noise?) 18, 19, 20, 22 0V (GND?) 21, 23, 24 2V, 32V const while printingAny suggestions welcome. I will try to hook up the logic analyst soon.
That sound fantastic! I have followed the Ultimaker project from the beginning and I have seen the printer at some Dutch trade show. I would be happy to share whatever I find out about the head as well.
I did manage to wire up the 24-pin connector in the print head board, and I found various voltage levels from 1.5 to 5V. I should be able to hook up the logic analyzer safely next week.
Most exciting stuff!
The first Z-Corp printers use this cartridge. They are over 20 years old by now IIRC. I had quite some trouble getting a reasonable number for my Z-Junker. The printheads barely survive a single print and need to be modified because they are one piece with the ink tank. The ink tank contains foam and can not be emptied or refilled. I had to use a hacksaw to decap it (huge mess with a full cartridge), then remove the innards and flush it, and finally glue in a cut-off test tube to get the ink system going. The color version is a combination of a hacked ink head with three tiny ink containers. The heads are quite rare. I have not found one that was working in three spare printers. An even if you get CIS going on those, you still need three heads for CMYK and Clear color.
I would see this cartridge as a slightly better HP C6602A that Plan B already uses.
OK, I have soldered 24 wires to the ribbon connector on the printhead. I want to avoid ruining my logic analyzer, so I tapped into all wires using a scope first to find the high voltage line that would destroy the logic analyzer’s input. So far, I have seen some weird noise on two pins, some digital data on three other pins at around 3.5V. No line carried more than 3.5V when testing. There must be a line though that supplies 18V or so for the heating elements.
I will try to create a repeatable test pattern for further testing. I also need to find my probes to avoid noise on the scope.
