Info for Epson Precision core printhead

Powder and inkjet printing
DDDoug
Posts: 6
Joined: Fri Feb 05, 2016 11:57 pm

Info for Epson Precision core printhead

Post by DDDoug » Mon Nov 14, 2016 4:09 pm

Has anyone had any luck driving the new Epson head?

I have one disassembled and I see the following: Of the 25 lines from the ribbon cable, there are several grounds and a pair of what appears to be power lines.
The actual head has 22 pins.
There is a two layer PCB between the two.
There are SMD caps and resistors on the PCB.They are mounted text side down.
There are eight pins with same value R-C to ground filter circuitry R=100 ohm and C measured at .1nF.
I imagine they could be data.
There look to be about eight other pins.
The print head has 800 jets.
I would imagine the other pins are as follows:
2 for drop size
1 for clk
1 for fire
1 for logic voltage
Here is what I found.
1 pin on ribbon cable side has a 10Kohm to ground.
A few runs have a cap to ground.

Does anyone have any schematics for these print heads to share?

DDDoug
Posts: 6
Joined: Fri Feb 05, 2016 11:57 pm

Re: Info for Epson Precision core printhead

Post by DDDoug » Mon Nov 14, 2016 4:42 pm

I have used the Epson SDK. There are some control features that are beneficial. However, the printer goes through start-up procedures and cleaning procedures that make it difficult to modify. I now need direct control of the printhead.

davidk
Posts: 69
Joined: Sun Mar 12, 2017 6:48 pm

Re: Info for Epson Precision core printhead

Post by davidk » Sat Apr 14, 2018 6:29 am

I just meet a friend of mine that has a large format printer and he gave me an Epson DX4 head and promised mea bag full of partial clogged ones.
It sems that anyone having a solvent printer can easily collect a ton of used heads that are just verygood for testing our projects
The good thing is these DX4 have two nozzle rows and separte manifolds. So this head he gave me is 100% working on one channel and partly clogged on the other. Chances are anyone can scrap heads in this condition, you just need to go to a banner making company and ask them to give you the heads they throw away anyway.

DX4 can work with solvent, UV and aqueous inks and would be more suitable than Xaar128 I think.
Other advantages:
Although more complicated driving signals, the fact that we can generate ejecting trapezoidal waveform would help us to adjust firing according to any liquid we use.
Another thing, as I'll describe later, ALL epson heads seem to use the same driving pattern so you can buy a new $50... 100usd new head for office printers and adapt in the same arduino or teensy firmware.

Well, after many hours of intefnet digging, I can say all Epson heads I studied were controlled exactly the same way, as I said before:
1. COM signal - a power amplified trapezoidal signal for piezo actuator motion
Other TTL signals:
2. NCHG - negative small signal, probably meaning drop size change or piezo discharge as someone said- i don't agree the later, I think N cames from Negative logic
3. LAT - this must be used to tell the nozzle data buffer demultiplexer latch that SPI data is loaded and it can be sent to nozzles
4. CH - don't know yet, there's a small "1" pulse after each trapezoidal COM pulse EXCEPT the time where NCHG is issued. So these two must work together to tell the nozzle demultiplexer which waveform to apply to eack nozzle or nozzle group
5 - SCK serial data clock, some heads have ballanced TTL input
6 - SI - serial data, here is the nozzle binary data and some drop size info (??). This also may be ballanced driver input.

Ballanced means therere are 2 pins for this function: positive logic and negative logic, in pair. This is to reduce interferences on long ffc cables.

I'll come back with DX4 pinouts on each of the two ffc connectors and some signal diagrams.

davidk
Posts: 69
Joined: Sun Mar 12, 2017 6:48 pm

Re: Info for Epson Precision core printhead

Post by davidk » Sat Apr 14, 2018 8:20 pm

Hi,

Here I found complete schematic of a Roland printer, including head control board:
https://www.scribd.com/doc/142024676/Ro ... ual-XJ-740
Unfortunately an account is needed but I got it. So this is the source of DX4 pinouts from my schematic.

Here http://techref.massmind.org/techref/pcb ... tom-vs.htm you can see very useful signal diagrams.
I found other documents that leads me to the conclusion that almost all epson heads have the same driving methods. I studied them and made this attached diagram; I don't say it's 100% correct, but it's a start for someone that wish to play with this head. I also made an incomplete schematic for wave amplifier and TTL inputs. Please look at it and maybe there's anybody interested and wish to experiment.
Again, a visit to any advertising company may end with many scrap printheads and caps they'll give you for free; these can be used for tests, so practically no expensive damages you can make.
Attachments
epson.zip
schematic
(55.62 KiB) Downloaded 163 times
New Doc 2018-04-14.jpg
head signals
New Doc 2018-04-14.jpg (403.07 KiB) Viewed 5146 times

math
Posts: 21
Joined: Tue May 24, 2016 1:08 am

Re: Info for Epson Precision core printhead

Post by math » Sat Apr 28, 2018 5:13 pm

Why not try with an inexpensive epson printhead used in home consumer printer ?

davidk
Posts: 69
Joined: Sun Mar 12, 2017 6:48 pm

Re: Info for Epson Precision core printhead

Post by davidk » Tue May 01, 2018 5:45 am

It makes sense, but it would take much time to extract the data like the guy in my link. The DX heads are very strong and are made for a wide range of fluids. They are expensive indeed but you can find used heads and/or with clogged nozzles very cheap or for free. Eventually you can buy new ones after building electronics and selecting ink.

david
Posts: 65
Joined: Wed Sep 21, 2016 8:43 pm

Re: Info for Epson Precision core printhead

Post by david » Wed May 09, 2018 11:20 pm

davidk wrote:
Sat Apr 14, 2018 8:20 pm
Hi,

Here I found complete schematic of a Roland printer, including head control board:
https://www.scribd.com/doc/142024676/Ro ... ual-XJ-740
Unfortunately an account is needed but I got it. So this is the source of DX4 pinouts from my schematic.
Thanks for your input. That's very useful information. Do you mind posting the rest of the circuit connected with the head from the manual?

davidk
Posts: 69
Joined: Sun Mar 12, 2017 6:48 pm

Re: Info for Epson Precision core printhead

Post by davidk » Fri May 11, 2018 6:54 pm

Here are the pages for the head driving. I can't attach here the whole pdf, it is a 16MB file.
Attachments
carriage board.zip
(361.62 KiB) Downloaded 199 times
head board.zip
(315.93 KiB) Downloaded 192 times

math
Posts: 21
Joined: Tue May 24, 2016 1:08 am

Re: Info for Epson Precision core printhead

Post by math » Sat May 12, 2018 5:15 pm

I just took this information from service manual about how epson describe the control lines. Pay special atention to the NCHG, that was described something diferent of the suposed before.
Attachments
pinout epson.PNG
pinout epson.PNG (40 KiB) Viewed 4940 times

fmpo
Posts: 1
Joined: Sun May 27, 2018 9:19 am

Re: Info for Epson Precision core printhead

Post by fmpo » Sun May 27, 2018 9:21 am

There is some work on adapting epson printheads and one group had fabricated a custom board:

here is the work that they have done:
http://cfg.mit.edu/content/multifab-mac ... d-printing

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