HP Laserjet 3005 Printing problem

[Leopardos]

Hello,

We have 3005 Printer in our office ,
Some times when we print , we have to manualy click the green button to continue printing documents ...
For example , when i print 50 pages , it works fine until 10 or 15 papers ... then i have to manualy click the Green button to continue printing the other pages ... and some times i have to click it for each page...

What could be the problem here ?

Thanks