Why YICAI3050 small printer stop printing, no printing?

Why YICAI3050 small printer stop printing, no printing?

YICAI3050 stop printing when the printing head goes down?
YICAI3050 small printer runs according the sensors.
If a sensor failure, the machine will stop working.
Automatic screen printing machine failure phenomenon:
After printing head down,but without printing;
Print head down for a long time,but withhout printing;
The solution;

Check the control panel above the "D" lights have bright;
If there is no light, then where is the sensors have no induction to the print head;
Sensors located in the lower lifting cylinder;
As the picture shows:

Replace the sensor or move sensors a little, slightly until sensor lights up;
Is there a way to damage detection sensors can also use the magnet proximity sensor, if the light sensors sensors work ~