CPU % User 50 always without working in the computer

Since last night I've noticed that in spite of only executing "Activity Monitor" for a long hour, the cpu % user is 50 something all the time. According what is being displayed the cores are completely busy in an alternate way. First one is in the 50% and the other idle 48%, then change, the idle comes active 50% and the active comes idle 48% and so on. A snapshot of the "Activity Monitor" display is shown.
The computer is anyway responsive. I have run all the updates, verify permissions, etc. Any comments?

Thanks

 

Looking "All processes" was the key to solve the issue. I found the process that was using heavily the CPU, killed it and things comes to normal again.

Thanks

 

I don't remember exactly what was its name but it was a printing job.