The ball material is a little soft and springy. The hole material is identical. I did not notice leakage. I have been using this design for many years. I have no problems.
EEPROM information contents
iP4200: Model name
Head TempBK=18.5 Head TempC=17.5 Env Temp=30.0 FF(3F 3F 3F)
Printed items:
30. Print head temperature (BK/CL) 31. Insidetemperature
16 DIK Diode sensor cathode IN
26 DIA0 Diode sensor anode 0 IN
38 DIA1 Diode sensor anode 1 IN...