I had 3 carts in a row with this problem - all 23 type.. (special problem of 23 ??? hmmmm)

It took awhile until i understood the problem completely, especially what I saw - it happens quick and is very small. After i got it and knew where to look and what to look for, it got more easy.

The following picture are copied out of a video. The whole sequence is just a second - so about every third picture is shown here.
What is seen is caused by blowing into the blue chamber - down-under of course.

(pictures are cut to the interesting size to reduce download time - therefore picture size may vary a bit.)
 

A few more explanations - help for the newbies.

The yellow line is between the yellow nozzles. The tiny "dots" left and right  of the line are the nozzles.
The red line is between the red nozzles.

The red oval is beneath the blue nozzles and showns little ink drops squeezing out of the "oval holes".
This oval holes shall separate the nozzles from each othere shall prevent ink from wandering between them.
These nozzles are not connectet with any ink reservoir. ( i got that out of the patent.)

The fact that ink appears there is proof enough  that the nozzle plate is loose.

The red nozzles are lying between red and green oval.

The green oval shows the rim of the nozzle plate - where the plastic bulge is situated.
In the middle is a dark area of the plastic - the ink has already squezed under the plastic!
(again proof the plate is loose).

Following the pictures, its hardly necessary to tell more - see by yourself.
 

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Now the ink squeezes out under the plastic rim.

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Until now no ink out of the nozzles !

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thats it.

I should tell this cart show the effect very easily, others I could only identify after I learned from this pictures whats going on by myself !

Last but not least - repair is impossible.