[wonko]

Ah, if you would have been in the EU, I could have sent you a logic analyzer for testing at higher frequencies. Bummer.

[wonko]

Wow. Great information. ezrec, in which country are you?

[wonko]

The Epson printhead connector is mostly known. It has a quite complex chip on board that requires a funky waveform on the high voltage input to generate 3 droplet sizes. They are awesome printheads, especially since they use piezzo technology. That gives them a much broader range of liquids than the HP heat based heads, and a much longer life span. I find them relatively expensive though.

[wonko]

@dragonator Well, I wish I had more time to dedicate to this. There will be no time this weekend, so I guess patience is required. I don’t see a need for you to buy a printer, unless you either are faster with testing, or you will want to verify my results ;-). Instead, it would be great to see a good ink cartridge clip and a mount to Plan B (or Plan C) come out of this.

@ezrec Yes, I agree. The connectors from the ribbon cable to the fixed PCB are much mach smaller than the connectors on the carriage, and I don;t know if I can solder there. By tapping right into the print head ribbon, I can get exactly what the printhead gets, which is what we plan to emulate. I expect a clock signal, a reset signal, a load signal, one or more fire signals and a bunch of data lines. The Power will probably be around 16V as you say. The logic however I expect at 5V or 3.3V. If that is true, we will no driver electronics at all and can connect right to an MCU.

[wonko]

OK, I received my printer today – probably the messiest ink jet printer I have ever layer my hands on!

A few things before I post the photos:

– the carriage is incredibly fast!
– the carriage contains an optical gate to count x positioning, and a reflective light sensor to sense ink head alignment
– the carriage has a PCB inside with two caps and an 8 pin unmarked chip
– the ribbon to the ink head has only 24 connections, and only 20 seem to be used. Many of them go to multiple pins on the head
– two traces are super wide, one is wide, the rest is hair-thin
– everything is soaked in ink
– HP is very smart: removing the scan unit gives full access to the print mechanics. The software recognizes the missing scanner, but still works as a printer. Wow!
– I did get it to print after cleaning and fixing the car wash. Now my hands are black, and the printer is white again 😉

So next I need to solder 24 wires that withstand the carriage acceleration onto the ribbon connector, reassemble the carrier, and then log the data arriving right at the print head. Fingers crossed.

[wonko]

That is a good idea. I ordered another printer for disassembly, awaiting delivery any day now. The reverse engineering then goes in a few steps:

First I need to get to the contact on the pcb, because adding hair wire to the print head, though possible, is tedious. After soldering tap wires to all contacts, I will verify voltages with a scope. This is needed to avoid damaging the logic analyzer in the next step. https://www.saleae.com has a great collection of those, and I am happy to have received one of the first of the new generation. Connecting those to the pins should make the protocol immediatly visible.

I also assume that we have multiple shift registers in parallel (clock, data, set), but there will likely be additional pins for firing, head temperature, and maybe other diagnostics. Plus GND, logic power, and nozzle power.

We will see.

[wonko]

<p>@draginator,
Do you want me to print an ink cartridge container for you?</p>

[wonko]

<p>@dragonator,
I ordered a second printer for disassembly alone. I really appreciate the printhead, and I think you are right. If there is electronics in the head, it may possibly connect right up to a CPU. The high- an low side drivers may (or may not) be inside the head already, making our life incredibly easy. But I will know for sure soon.</p>

<p>@Ezrec,
This has the advantage to possibly need less electronics, but it has the disadvantage that a builder must find an entire printer, instead of just a head. Then again, I hav bought two entire Photosmart printers for less than the printhead inside… .</p>

[wonko]

<p>Yes, I printed them myself. This is basically an unmodified XYZPrinting machine with good quality filament and second to best printing setting. I am very happy with the machine. The results are better than this of my old BFB Touch that cost 8 times as much and isn’t serviced at all anymore (less than two years after I bought it – a total loss in every respect. I would never buy anything from 3D Systems again).</p>

<p>I do have a little tool that fixes some imprecissions of the machine (all models come out 0.1mm to thick), but other than that, this is straight out of the machine.</p>

[wonko]

<p>I hope that your 3D printer repair is going well.</p>

<p>After I originally ordered a Photosmart All-In-One printer with the right print head, I started using it and I am so happy with it as my daily machine that I can;t reverse engineer it 😉 . I ended up grabbing another printer from EBay. It costs less than the printhead alone. Let’s hope that it arrives soon, and that my Saleae logic analyze will deliver the data I need to understand the protocol…</p>

[wonko]

<p>Phew. Seeing all the 3D printed ABS parts, it’s quite a bunch ;-)</p>

<p></p>

[wonko]

<p>I am currently building the Plan B. It’s great to see that there are printheads that seem to resist some harsh solvents. Currently though, I have to build the machine first, using the print head described in the manual. As soon as I have repeatable results, I will likely switch to another head. However, my focus then is on the HP CN642 simply because it is a fast head with the required five colors for full color 3d printing.</p>

[wonko]

<p>ABS powder can be bought for about 1 EUR per kg, for example:</p>

<p>http://plasticker.de/recybase/ABS_PULVER_natur_rb192905</p&gt;

[wonko]

<p>Hmm, well, it would be great to know the connections on the cartridge. This looks like a matrix one. If we can control it, we can mount it on a Plan B machine and print with Acetone on ABSS powder… .</p>

[wonko]

<p>Oh, very nice! Thanks for trying this out. Do you have electronics to control the jets?</p>

[Author]

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