Comparing Piezo heads with thermal inkjet heads

[turbguy]

I think I read that you can damage piezo head (EPSON) very easily if you do multiple deep cleanings in row like 15-25 cleanings. Perhaps the piezo transducers overheat, you know like in ultrasonic bath (you can't run those without water).

And bad CIS systems result in piezo head failues too, since mostly everyone is using CIS from china on EPSON that is. If a printer using piezo is used with bag type carts like EPSON, I'm sure it will outlast any canon printer but head replacement will be 2x more than canon. Just confirmed this on 4700D head vs. L800 piezo head.

True, it is possible to damage piezo heads if abused. BUT...have you noticed that the VAST majority of Canon print head failures posted here are from significant electronic failures? Those failures exhibited by large banks of nozzles stopping? The current density in the conductors, switches, and heaters is VERY HIGH compared to a piezo element, where MUCH smaller currents are required. In actuality, it doesn't seem to be individual bubble-jet nozzles that fail, but rather some circuitry removed from nozzle. The firing current just POURS into thermal print heads, requiring localized protection (temp sensors) that trigger a cool down pause from time to time during extended use. That is the number one reason I opt for slower printing ("night mode") in all my Canons. Slower printing equals less heating.

Ultrasonic cleaners have piezo elements that operate continuously when in use, not so for a print head...unless it's during a cleaning cycle.

I have a "Chinese" CISS on my Epson Artisan 800. Is it trouble free? No. Has it caused a single nozzle failure? Not over three years of operation.

 

[Smile]

That is the number one reason I opt for slower printing ("night mode") in all my Canons. Slower printing equals less heating.

I was thinking only print head moves slower in this silent mode, how do you know the current for print head is less?

Ultrasonic cleaners have piezo elements that operate continuously when in use, not so for a print head...unless it's during a cleaning cycle.

Yes I was talking about cleaning cycle, with empty piezo print head (for example deep cleaning with CIS problems).

I have a "Chinese" CISS on my Epson Artisan 800. Is it trouble free? No. Has it caused a single nozzle failure? Not over three years of operation.

I'm still debating should I get 4700D printhead or EPSON L800, there is very wast amount messages that L800 prints with streaks of white lines if used in any mode except Prohot RPM, best photo with EPSON ink. Seems like nonsense to me.

My brother MFC-5895cw has piezo head, less nozzles never streaks even in plain paper mode. So something wrong with L800 printheads or CIS system that EPSON designed.

 

[Smile]

This is a nice comparison material or thermal and piezo heads by HP, it's not new but has many points shown.
http://h10088.www1.hp.com/gap/download/oeminkjet/techpress_1.pdf

Also this is another scientific comparison with images
http://doc.utwente.nl/58366/1/thesis_Wijshoff.pdf

 

[mikling]

These are good articles.
In the first, namely page 24, refers to some key problems in the early Epson printers. My experience has shown that it is not encrustment but rather air trapped internally due to bubble nucleation. This issue has led to so many CISS vendors indicating that clamps are required to prevent this while of course they are not required and the build up of bubbles at the printhead was due to a different phenomena. It is hard for many to understand and many think encrustment is the sole cause but most times it is not. Encrustment, perhaps for long term storage but this is the exception rather than the rule.

The first article is rather dated now. It is done by HP and has an HP bias. Many more advances have been reached since then with Piezo and the drop size is now down to I believe as low as 1.5pl. What is not mentioned is that drop pattern and dot shape is more predictable on piezo heads. Additionally the technology has advanced to the point where the ink on the nozzle tip is stabilized between firings (shooting) by modulating the nozzle itself. Think of a glass of liquid. Disturb the liquid and you get circular waves generated on the surface. Now if the frequency and timing of the wave is within a certain window, it will disturb the next firing. To minimize this, think of cycling the glass itself so that the liquid settles down quickly. I don't see it settling but I see a higher frequency disturbance that will eliminate resonance. But this is where piezo heads have gone to now. In addition to this particular models are teflon coated and some have +400v internally to attract stray ink spray. Additonally new piezo materials have been introduced which allow much high nozzle counts but this will never approach the amt a TIJ is capable of for obvious reasons.

The first article makes mention of no pump required on TIJ. However, we know that Canon printers with separate heads have these pumps.

If you read the article it will allow an understanding of the issues facing both technologies and allow understanding of how they both have moved forward.

 

[turbguy]

I was thinking only print head moves slower in this silent mode, how do you know the current for print head is less?

Instantaneous current density (Amperes/square mm of conductor) of individual nozzle heaters remains the same, but total current flow to the head is reduced as slower print head movement must mean slower nozzle firing per unit time. It gives the print head better ability to dissipate the heat produced, too.

 

[Smile]

Here is how brother piezo print head looks like, very advanced I would say unlike the ones used on epson P50/T50, 1500W, R2880 etc.

No teflon that wears off, and no stupid metal cover that traps so much sludge during cleaning cycles that eventually blocks the nozzles.

Can you believe I haven't had to do a single cleaning manually on my brother mfc in about 8 months of having it being used sparingly? I changed the BK ink from pigment to DYE for purpose of printing on glossy photo paper, had to do 3 cleaning cycles to purge the lines and then print some 15 pages A4, then 3 cleaning cycles then 5 pages more. Prints are sharper than my old 6700D with 1pl droplets.

I wonder who make printheads for brother, are they making them themselves? Why they do not have 6 color printers if they reached this quality level?

 

[thanhhuy123]

Wow, so Epson is behind Brother even though they are the owner of piezo printhead!
BTW, can Brother be used with CISS? I hear many Epson with CISS, but not yet with Brother since I don't hear much about Brother chip and ARC for it?

 

[Smile]

You don't need CIS for brother, it's built in.
http://welcome.brother.com/sg-en/our-technology/printing-imaging/inkjet-printing.tab2.html

Only let me say "dumb" manufacturers use the cartridges in print head approach, this is not used in desktop printer by Canon, EPSON because it makes printer to wear faster. Only Pro models and wide format has ink cartridges separated.

But Brother has done the homework, they separated the cartridges for all their printers.

Brother has 1.5pl same as EPSON.
http://welcome.brother.com/sg-en/our-technology/printing-imaging/innobella.tab2.html

But there are not Light inks I asked them about it they told they cant disclose any information if they are going to have a photo printer.

 

[Smile]

Oh forgot to mention you can get L800 from EPSON with built in CIS, I've managed to find them with 2year warranty locally. And perhaps I'm going to get one to try.

I would like to use the EPSON ink, as it is better for longer lasting prints, and my Canon dealer replied that they can sell me printheads for my 4700D but if I would like to get warranty I would have to bring my printer to them, use genuine ink, the printer would not have to be modified etc. In other words I would get no warranty. If so I could risk and buy the print head from china for 25Eur, instead of 50Eur.

 

[thanhhuy123]

Epson vs Brother, anyone has any idea??