Besides the printing cylinders used in the flexo and rotogravure printing machines, those are very special cylinders for various industrial sectors and for various purposes, such as:

Cylinders for web printing machines used for the printing of newspapers, journals, magazines, etc
Heating cylinders
Cooling cylinders
Pressing cylinder
Embossing cylinders

Those are the cylinders used in the rotogravure printing machines.
Those cylinders are coated by nickel and cupper and engraved.
The function of the cylinder is to transfer the ink to the web material through the engraved surface.