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.

 

[patuga]

Last (and only time i had to do it) head i purchased was 2600€ + vat.
i searched and saw a website that sells them for 420€

PrintheadAvailable.com

PT. Printhead Available is a leader in sales of large-format printer technology. Years of experience in the field of ink jet printing allows us to compete at a

printheadavailable.com

does anyone know this company?

 

[Smoke_Jaguar]

If it's Indonesia, and it is, it is a scam.

Last (and only time i had to do it) head i purchased was 2600€ + vat.
i searched and saw a website that sells them for 420€

PrintheadAvailable.com

PT. Printhead Available is a leader in sales of large-format printer technology. Years of experience in the field of ink jet printing allows us to compete at a

printheadavailable.com

does anyone know this company?

 

[patuga]

Damn... i really don't want to buy a new head when this one is printing without a problem. Specially since it's a lot of money. If that store was legit i would bite the bullet for 400€ but for 2600€ i really need to think about it.

I'm tempted to try the resistor trick to get the head temperature up.

now i'm having problems with the printer not powering down when doing regular maintenance. Not sure if it's related to the head temperature issues or if it's unrelated. i had this issue before 3 months ago. the tech guy came and updated the firmware and after a few days the issue when away. two weeks ago it started happening again. frequently it displays a message "please wait flushing"

Also the white is failing. it starts printing and it seems to run out of ink midway. Frankly this printer has been nothing but problems since the start

Is the flushing function done by the air pump? could this be a problem with the pump not being able to keep the pressure stable? when i test both negative and positive pressure, they are within the parameters (16.7 for positive and -2.30 negative), but it doesn't mean it couldn't drop during a large print.

 

[patuga]

currently my head temperatures are:

39ºC
40ºC
27ºC
34ºC
36ºC
34ºC
39ºC
39ºC

both primer and white heads have been swapped and the yellow/cyan and magenta/black heads are original.

not sure if the temperature is too low for the maintenance to occur without any problems. two weeks ago, ambient temperatures dropped maybe it caused the temperatures to go bellow the 30ºC.

Will try to warm up the print heads area with a heater to see it it makes a difference.