I guess this cry of frustration has been heard ever since Caxton invented the printing press [if it was actually him]
The thing is, the machine is trying to control the paper and the paper has a mind of its own.
This makes life difficult because the client perceives the jam as a fault of the machine and provided the machine is up to the standard that it left the factory, the technician perceives it as a fault of the paper. There is not a machine made yet that doesn’t jam at some time or other, all we can do is minimise them happening.
So what can you do?
First a few words about paper …. Paper is cut from a giant roll, the paper on the outside of the roll is forced to go through a gentle curve, the stuff from the inside of the roll is forced to go through a tight curve and that’s the way it wants to stay, curved. Technicians say “the papers damp”, wrong phrase actually, what they should say is “the moisture content is high” because when the moisture level in the paper goes high the paper wants to return to its roll shape, to stop this, all you can do is store the paper in a warm dry place.
To work properly the machine needs to have nice flat paper, so it can control the paper through its paper path mechanism. So what happens when the curved paper goes through the machine, it jams, this explains why sometimes jams that only happen when the paper is placed in the paper cassette a certain way up, the curve works with the machines paper guides rather than against the paper guides, turning the paper stack over in the cassette is certainly worth trying. It also explains why jams that only happen when you duplex, this is because the paper takes a more complicated path through the machine therefore more chances to jam.
And how do you test if the paper is going to jam?
Do twenty prints and then take the printed stack from the output tray and hold it between thumb and fore finger, hold it on the short edge of the paper in the middle, on A4 paper at the 105 mm point, hold it at the top and let the stack hang down.
If the paper stack takes up a curve, there is the problem and there is the answer to why your machine is jamming.