The blanket cylinder on a offset press carries the blanket and has two primary functions.

1. To carry the blanket in contact with the inked image on the printing plate.

2. To transfer (offset) the ink image to the substrate carried by the impression cylinder. It is similar to the plate cylinder in that it has a gap, gutters, bearers (sometimes), gear and bearings. It does not have clamps, but has reels for holding the blanket tight.

The position of the blanket cylinder must be adjustable for two reasons

1. To bring it in and out of contact with plate and impression cylinders.

2. To compensate for variations in substrate and packing thickness. The blanket cylinder is undercut to accommodate the blanket and packing.