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Re: Hacking the Xaar 128 printhead

Posted: Sat Mar 03, 2018 7:24 pm
by BlueTurtle
Hey everyone,

I have gotten the printhead to work and can print what ever pattern I want but I have another question before I fry anything. I have seen all of you use relays to control the 35Vs and I was wondering if I can use Mosfets rather than relays. The documentation states in the page 35 that "The negative side of the logic and high voltage supplies should be isolated within the driver electronics, note that they are joined within the printhead and must not be joined at any other point.". Does that mean that the only solution to power the electronics is using Relays since mosfets are not isolated?

Re: Hacking the Xaar 128 printhead

Posted: Sat Mar 03, 2018 7:54 pm
by davidk
Hi,

Indeed, working with high voltages and digital signals can be troublesome. For a prototype setup like ours, I would use relays.
What ink do you use? How do you store the printhead so it won't clog?

Re: Hacking the Xaar 128 printhead

Posted: Sat Mar 03, 2018 8:09 pm
by BlueTurtle
davidk wrote: Sat Mar 03, 2018 7:54 pm Hi,

Indeed, working with high voltages and digital signals can be troublesome. For a prototype setup like ours, I would use relays.
What ink do you use? How do you store the printhead so it won't clog?
Yeah as of now I use relays but I will try mosfets too.

I just use an alcohol based ink and the printer indeed clogs. When it does I clean the nozzles with a wipe soaked in ethanol. Also I force IPA through the printer with a syringe. After all that I fill the nozzle with ink again with syringe and force ink through it. It is troublesome but works until I design a capping station for it.

Re: Hacking the Xaar 128 printhead

Posted: Mon Mar 05, 2018 8:52 am
by Wonko
I use mosfets. I believe that the reason behind separating the ground lines is keeping the 35V sources as independent as possible. One 35V line is used to supply the power to the piezzos and needs power, but less stability. The other one is used as a reference voltage and should be very precise to keep ink drops exactly the same size over time.

I have achieved that - I hope - with a single 35V source that I split into two, using a different filter on each. The first 35V line has big caps, the second line has smaller caps and some noise reduction. They are then switched by a mosfet. Operation is smooth.

As for the ink, professional printing supply companies sell the correct ink for the head. Unfortunately, the heads are pickier than I originally though.

Re: Hacking the Xaar 128 printhead

Posted: Sat Mar 10, 2018 12:32 pm
by davidk
Hi BlueTurtle,
Can you give me more details about your ink?
Are you sure IPA won't damage the head?

Re: Hacking the Xaar 128 printhead

Posted: Tue Mar 27, 2018 10:12 pm
by aengel
Philipp wrote: Mon Feb 26, 2018 2:52 pm Hello, guys,
I managed to reduce the CLK signal to 1MHz by increasing "OCR1A = 11; //7;" from 7 to 11.
When I look at SCK, the frequency is much higher than 1.4 MHz. Is that admissible?

TCCR1A = _BV (COM1A0); // toggle OC1A on compare match
OCR1A = 11; //7; // top value for counter OCR1A = Pin11
// UNO //TCCR1B = _BV (WGM12) | _BV (CS10); // CTC mode, prescaler clock/1
TCCR1B = _BV (WGM12) | _BV (CS10); // CTC mode, prescaler clock/1

regards
Philipp
Hi Philipp : I wish to buy several of these X inkjet boards. Please contact me. Thanks, AE

Re: Hacking the Xaar 128 printhead

Posted: Thu Mar 29, 2018 5:01 pm
by aengel
Very low viscosity uv curing ink ingredients are available from Allnex. They are very easy to formulate and have viscosities at room temperature under 10 cPs.

Regarding solvents for inkjet printheads, IPA should be OK, but it must be filtered with a 0.4 micron filter before use. Some workers recommend 0.2 micron filters for inks which have particles and nanoparticles such as silver nanoparticle inks.
BlueTurtle wrote: Sat Mar 03, 2018 8:09 pm
davidk wrote: Sat Mar 03, 2018 7:54 pm Hi,

Indeed, working with high voltages and digital signals can be troublesome. For a prototype setup like ours, I would use relays.
What ink do you use? How do you store the printhead so it won't clog?
Yeah as of now I use relays but I will try mosfets too.

I just use an alcohol based ink and the printer indeed clogs. When it does I clean the nozzles with a wipe soaked in ethanol. Also I force IPA through the printer with a syringe. After all that I fill the nozzle with ink again with syringe and force ink through it. It is troublesome but works until I design a capping station for it.

Re: Hacking the Xaar 128 printhead

Posted: Thu Mar 29, 2018 5:06 pm
by aengel
Has anyone attempted interfacing this device with RIP shareware such as Onyx Graphics? or in Asia, MainTop? or performance testing shareware such as PrintMon? (Note that PrintMon may only be available for Seiko heads, although I have read hints that it has been adapted to the Xaar as well). Any suggestions? Thanks, Allen.


Wonko wrote: Mon Mar 05, 2018 8:52 am I use mosfets. I believe that the reason behind separating the ground lines is keeping the 35V sources as independent as possible. One 35V line is used to supply the power to the piezzos and needs power, but less stability. The other one is used as a reference voltage and should be very precise to keep ink drops exactly the same size over time.

I have achieved that - I hope - with a single 35V source that I split into two, using a different filter on each. The first 35V line has big caps, the second line has smaller caps and some noise reduction. They are then switched by a mosfet. Operation is smooth.

As for the ink, professional printing supply companies sell the correct ink for the head. Unfortunately, the heads are pickier than I originally though.

Re: Hacking the Xaar 128 printhead

Posted: Wed Apr 04, 2018 7:34 pm
by Restani
I have the same problem with Philipp in my project, all the nozzle shoot together.
In my case the CLK is at 1MHz as is the SCK.
I'm using a mega arduino. Using an oscilloscope I could see that CLK and SCK are not synchronized in the project. Do these signals need to be synchronized?
I have a device that uses XAAR 128, and it has CLK and SCK synchronized.
This equipment uses an external 1 MHz oscillator.

Re: Hacking the Xaar 128 printhead

Posted: Thu Apr 05, 2018 7:55 am
by Wonko
The clocks don't need to be synchronized. They can have completely different frequencies. The data clock can have up to two MHz. It's all in the manual: XJ128 Guide to Operation, Xaar Document no: D031010302 Version A, Page 33. Just make sure that you stay within the limits and verify all assumptions with a decent scope. Also, make sure you use proper ink (water for example will not work!) and the head has not been damaged in earlier attempts.