The unwinder includes an unwinding station, in which to arrange a reel to be unwound. In the unwinding station there is arranged a series of guide rollers, defining a feed path of the web material. There are also provided: a cutting member adapted to cut a web material coming from an exhausted reel; and splicing members to splice a trailing edge of a first web material coming from an exhausted reel to a leading edge of a second web material coming from a new reel. A pick-up device is configured to pick up the leading edge of the second web material from a temporary retaining element, carried by a transfer unit to transfer reels to the unwinding station.

Paper converting plant, including means for producing logs of paper material starting from one or more paper webs fed by corresponding reels, an embossing unit, a bridge crane with arms provided with grippers, and a rewinder that produces logs using the webs coming from the embossing unit, wherein the embossing unit is arranged to be configured in a first use configuration in which one or more embossing rollers positioned inside it are stably locked to respective support means and a second removal configuration in which said one or more embossing rollers are disengaged from said support means and can be extracted from the embossing unit, the plant also includes a storing unit in which are stored one or more embossing rolls according to a predefined storage order such that each embossing roller occupies a predetermined position in the same storage unit, each embossing roller having a respective longitudinal axis.