Can I use T6641 ink instead of T7741

binabdilwali

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Hi everyone

I have a quick question.

Currently, I am using the Epson L655 printer. I ran out of black ink, and the recommended ink by Epson is T7741, however it is unavailable in my region. My question is if I can use the T6641 instead which is widely available.
They seem to be identical, but according to Epson, I shouldn't use it.

I appreciate a definite answer on this, since at the moment I am stuck with no other option but to use the T6641, but I don't want to risk damage to my printer.

Thanks a lot in advance!
 

Ink stained Fingers

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These inks are not identical, I would assume from Epson's logic and ink numbering assignments that the T664x inks are dye inks and the T7741 black is a pigment black. This may have a slight impact onto the print quality, edge definition, if you use a dye black instead of the pigment black ink but it won't damage the printhead, that T6641 black is widely used with other printer models.
 

maximilian59

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Maybe you can get the T512/T105 inks, which are for the ET-77xx printers. This is also a pigmented ink. But I can't tell, whether it will do any harm to your printer.
 

Phill ODonoghue

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Please note that the T512 Black ink in Pigment but the BK (photo black) and all of the colors are Dye ink.It would pay to ensure that you have the right black.
 

soysauce

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I could measure the viscosity and surface tension of T7741 and compare those to T6641 if that would help. It would take a bit of time, so please let me know if you want me to get that data for you.

If you did want to use T512 you'd need to work around the keyed cap design used on T512. T774 and T664 both have unkeyed caps which makes them easier to interchange. (I guess I could measure surface tension and viscosity on T512 too if requested...)
 

binabdilwali

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Thank you all for your input.

I apologise for the late response, I was expecting to get email notifications for all news posts but for some reason they didn't come through.

I could measure the viscosity and surface tension of T7741 and compare those to T6641 if that would help. It would take a bit of time, so please let me know if you want me to get that data for you.

If you did want to use T512 you'd need to work around the keyed cap design used on T512. T774 and T664 both have unkeyed caps which makes them easier to interchange. (I guess I could measure surface tension and viscosity on T512 too if requested...)
That would be amazing since it would put me and countless others I'm sure forever at ease.

These inks are not identical, I would assume from Epson's logic and ink numbering assignments that the T664x inks are dye inks and the T7741 black is a pigment black. This may have a slight impact onto the print quality, edge definition, if you use a dye black instead of the pigment black ink but it won't damage the printhead, that T6641 black is widely used with other printer models.
I found quite a few people saying that they are both black pigment inks, why doesn't Epson share this info with their customers?
 

Ink stained Fingers

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I must admit I'm lost - did you try the other ink already - or if not what is holding you up ?
 

binabdilwali

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I have actually bought it today. But just wanted to be certain before trying, I've seen some people on some forums complaining about the print head getting clogged up after trying to use the T6441 on L655
 

soysauce

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Here are my test results. Viscosity is in centipoise (cp) at about 25C. Surface tension is in dynes/cm.
T774120: 2.2 cp, 26 dynes/cm
T664120: 2.5 cp, 29 dynes/cm
T512201: 2.1 cp, 25 dynes/cm

I'm not sure what to do with that data. 664 looks to be a little more viscous and have a slightly higher surface tension. I don't know if they are high enough to increase the risk of clogging the print head. On the other hand, if 664 is a dye rather than a pigment it might tend to clog less?
 

soysauce

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These inks are not identical, I would assume from Epson's logic and ink numbering assignments that the T664x inks are dye inks and the T7741 black is a pigment black. This may have a slight impact onto the print quality, edge definition, if you use a dye black instead of the pigment black ink but it won't damage the printhead, that T6641 black is widely used with other printer models.
How does Epson's ink numbering system work?
 
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