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AM336-Clean the bleed Valve for a stable Meniscus.docx


My meniscus is not stable, it goes from 0 to -0.50 psi.

It was fine last Friday and now it is not stable.

Reason #1: the bleed valve is clogged

The bleed valve or needle valve is very important; most of the vacuum applied by the meniscus pump is dissipated by the bleed valve. It is very important that it is free and clean.

Depending on the environment, we have noticed that dust or other particles can accumulate in the bleeder valve, making the meniscus unstable.

To clean it, just unplug the tubes, unscrew the needle, clean the valve with Alcohol or Acetone, test it with vacuum, then screw back the needle and put all back.

Do this every 6 months when you change the ink filter.

Check also that the PWM is within reason. Check manuals for the settings of the PID controller of the meniscus pump.

You might have to exchange the valve it if it was tightened too much.

Part -Number of the meniscus needle valve is 50002 and the price is $45.

Where do you find it in the eZ ? on the side of the cabinet



Where do you find it in the eZ Epson I3200 ? In the mount where the ink bottle is, by the meniscus pump (see here the white dust). Attach a wipe to the entrance if it is very dusty



Reminder of manual: remember that the Epson I3200 setting is -0.20, not -0.50 like others

How do you see that ?    here you see the actual value and here the setpoint. This is the Output (here 1.83). Try to keep the error E low



You can see here that the PID value is:

P: 0.1

I: 0.1

D: 0

The actual output to the pump is 1.83 and it is between the Min of 1.7 and the max of 2.0. You want to be between the minimum and the maximum.

Now, if you turn the relief valve and open it a bit (turn left). You will see that the vacuum falls from 0.50 to say 0.48.

When the control sees that, the output will go up from 1.83 to may be 1.87 until the actual value return to -0.50 which is the setpoint.

Of course, if you open the relief valve too much, the output will reach the maximum of 2.0 and it will not go beyond it. Hence, you will not achieve the desired vacuum of -0.50 because the relief valve is too open.

Thus, you have to slowly turn right the relief valve until the vacuum is around -0.5 and the output signal is in the middle between the minimum and the maximum. Around 1.86 

Reason #2: there is ink in the meniscus line

We have a sensor and it should tell you that ink came into the meniscus line. The only way to check this is take the cover of the head off and check the meniscus lines