Need Help UJF-6042 MkII Head Temp. Control

[Smoke_Jaguar]

I've put new thermistors in some heads, and the CE4N heads aren't bad to work on. To my knowledge, the thermistor deltas are hard coded, as there are no normal instances where thermistor type should change. More a Toshiba problem than a Mimaki one, as they make the heads. As for the MKII versus the MKII e, the biggest change is the paint job and some automation control stuff I have never seen actually being used in the wild.

 

[dudeinthemoon]

Thats how CE4 printhead looks like inside. The thermistor goes inside the ink chamber, glued there and cannot be replaced. But it goes straight to the printhead connector, pins 19 and 20, and theoretically, if you add a 9-10 kOm resistance between those pins the head will be constantly seeing 35-40C, in case if the head sees temperatures abnormally and causing errors

 

[Mrkopr]

We had this issue 3 months after installation. (white head) Lucky for us it was still under warranty. It seems like a common problem with these as our tech confirmed, they should treat it like cars, since they cost as much as one. A factory recall issue and should extend past any warranty.

 

[julesk]

View attachment 174880 View attachment 174881
Thats how CE4 printhead looks like inside. The thermistor goes inside the ink chamber, glued there and cannot be replaced. But it goes straight to the printhead connector, pins 19 and 20, and theoretically, if you add a 9-10 kOm resistance between those pins the head will be constantly seeing 35-40C, in case if the head sees temperatures abnormally and causing errors

Wow, it's cool to see inside one of these printheads. Do you have any more photos or diagrams you could share? I'm curious about the heating block and what the hot water path looks like inside the head assembly.

 

[patuga]

I've put new thermistors in some heads, and the CE4N heads aren't bad to work on. To my knowledge, the thermistor deltas are hard coded, as there are no normal instances where thermistor type should change. More a Toshiba problem than a Mimaki one, as they make the heads. As for the MKII versus the MKII e, the biggest change is the paint job and some automation control stuff I have never seen actually being used in the wild.

How do you replace the thermistors?

 

[patuga]

View attachment 174880 View attachment 174881
Thats how CE4 printhead looks like inside. The thermistor goes inside the ink chamber, glued there and cannot be replaced. But it goes straight to the printhead connector, pins 19 and 20, and theoretically, if you add a 9-10 kOm resistance between those pins the head will be constantly seeing 35-40C, in case if the head sees temperatures abnormally and causing errors

could those resistors be added to the flat cable? scratch the surface to expose the copper trace, and add it there. should be safer to do like that, no?

 

[Smoke_Jaguar]

How do you replace the thermistors?

Not easily, best just buying a new head if the thermistors are bad.