We do hope that our tests will be able to provide some useful data for everyone.
And yeah, apologies for the awkward "we;" the we was referring to my group, which consists of a few people, and I am working as the primary interface for the forum.
We are going to measure 8 different contacts 41, 43, 45, 47, 49, 51, 27, and 28, according to the map on the first page.dragonator wrote:Hello and welcome.
I (We?) indeed seem to be working on the same thing as you are. If you want to do the measurements, I would be extremely grateful. I am not yet at a point where I have give up with my experiments here, but getting a proper readout from an original HP45 printer would save me a huge amount of time. At this point I am fairly certain that the pinouts on the first page of this forum are correct, after this weekend I should be sure. That may help you narrow down what to connect to.
We are after the same thing, so I would be happy to collaborate. I am more of a mechanical man myself too, but I do have enough knowledge to make electronics if I completely know how the HP45 works. Even better is that most other people on this forum know much more than me about electronics and can probably do a lot better than me if they want to. And if all else fails I have the combined knowledge of the Tkkrlab (hackerspace Enschede) available. Electronics should be possible after the printhead is hacked.
How many channels do you plan to measure at once?
Our oscilloscope will be able to measure 4 channels at once. We plan to simultaneously measure corresponding primitives and grounds (e.g. Primitive 9, Ground 9) and an address contact. We will also test the Thermal Sense and Resistor contacts, but at this point I am not sure what combination of contacts will be tested simultaneously beyond the ground/primitive/address.
Also, right now we plan to run the tests on Friday, but depending on our different schedules, it may get pushed back (hoping not, though).
Thank you for your insight! On a past printer, we have tried to read directly from the ribbon cable, but it appeared that the output was a serial signal and we could not isolate individual control signals. At this point, since current printer's ribbon only has 20 pin and there are 104 contacts (52 for black, 52 for color), we figure this current printer sends a similar serial signal to its printhead.ezrec wrote:I would suggest that for your application, you focus on the ribbon cable to the printhead controller, personally, instead of the printhead itself.
I did some prior work for the HP F4480, which seems to use a similar controller, but my scope was not up to the job:
http://www.evillabs.net/index.php/Proje ... Controller
Since we are looking for more isolated control signals, we think that for the time being, it will be more useful to go direct to the printhead, as the signals here have already been processed and isolated further by the printhead from the ribbon cable's outputs. Though, we may still look at the ribbon cable in the future depending on what our success is/what other data is necessary.
Thanks for your help, but sadly we're not very clear what you mean by the identification circuit.DigitalShadow wrote:Welcome to the project! looks like you will be able to get some great data with that
Something of note, if my understanding of the patent is correct, the address lines are connected to both the primitives, and an "identification circuit". This identification circuit gets its inputs from the address lines, and is also shared with the temperature sense lines in an effort to reduce pin count. It seems that low voltage is used to poll temperature queries, and high voltage is used to poll information regarding the current cartridge, such as manufacturing data and such (Confirmation of this is still required. Getting this infromation from this patent from the beginning of this thread, last few paragraphs)
Also, my PCB's arrived today. They look greatStill waiting on the pogo pins and driver chips to arrive. I will likely focus on temperature control and monitering. Likely submerging the tip of the print head into an appropriate liquid solution and controlling the bath's temperature to a known value.
Is there any chance you can explain further?
(I have an idea of what you might mean; on the theory page on the InkShield project, they describe the control theory they used to reduce their pin count since the arduino only has so many outputs. In the end they designed a system with a multiplexer that selected a nozzle via 4 different lines ABCD prior to sending the firing pulse. Is this perhaps similar to the identification circuit that you mentioned?)
