Sometimes I have problems with biro pens.When I try to write with them the ink wont flow properly and it appears that they have run out of ink when they havent.Sometimes the ink pours out the wrong end.Im not sucking them or keeping them in my pocket or close to my body.Nor am I holding them for any length of time.One week I went through 5 or 6 pens a day.It seems to happen only with black ink pens.Can anyone explain why this happens?
If the pens appear to have run out of ink simply put the nib between your teeth and slowly breathe out hot air. This should warm up the ink and get it flowing around the ball.
It also sounds like a case of cheap pens and that's why they're leaking.
Are you leaving them somewhere warm? window/above a radiator/computer? This would dry the ink on the nib and also cause it to expand out the top of the pen.