A media roll holder assembly for a roll is detachably supported in a printing system. A rotational drive includes a roll engaging element configured for fittingly engaging and driving a drive engaging element of a roller, for example an Oldham coupling. A first guide surface is configured to support and direct the roller in a loading direction. A second guide surface at least partially extends at an angle with respect to the first guide surface, such that movement of the roller over the first guide surface brings the drive engaging element in contact with the second guide surface. The second guide surface directs the drive engaging element into a predetermined orientation, which orientation aligns the drive engaging element with the roll engaging element in a loading orientation, such that further movement of the roller in the loading direction inserts the drive engaging element into the roll engaging element.

A friction shaft for a slitter has winding tubes disposed on an outer surface thereof to roll unit materials formed by cutting a raw material such as various kinds of paper, fabric, or film with predetermined intervals. The friction shaft includes a first rotary shaft, tubes, lug bodies for torque, first fixed shafts, brake pads, a second rotary shaft, guide members, lug bodies for clamping, second fixed shafts, a plurality of lug rollers, covers, a first elastic member, and second elastic members.

A media roll holder assembly for a roll is detachably supported in a printing system. A rotational drive includes a roll engaging element configured for fittingly engaging and driving a drive engaging element of a roller, for example an Oldham coupling. A first guide surface is configured to support and direct the roller in a loading direction. A second guide surface at least partially extends at an angle with respect to the first guide surface, such that movement of the roller over the first guide surface brings the drive engaging element in contact with the second guide surface. The second guide surface directs the drive engaging element into a predetermined orientation, which orientation aligns the drive engaging element with the roll engaging element in a loading orientation, such that further movement of the roller in the loading direction inserts the drive engaging element into the roll engaging element.

A telescopic pneumatic linear actuator, particularly for unwinders with movable arms, includes a first annular cylinder, provided with a respective cavity, and a second annular cylinder, which can be inserted into and can slide within the cavity of the first annular cylinder and is provided with a respective cavity. The actuator also includes an annular piston, which can be inserted into and can slide within the cavity of the second annular cylinder. The first and second annular cylinders and the annular piston are provided with respective holes for the passage of a self-expanding spindle.

A friction shaft for a slitter has winding tubes disposed on an outer surface thereof to roll unit materials formed by cutting a raw material such as various kinds of paper, fabric, or film with predetermined intervals. The friction shaft includes a first rotary shaft, tubes, lug bodies for torque, first fixed shafts, brake pads, a second rotary shaft, guide members, lug bodies for clamping, second fixed shafts, a plurality of lug rollers, covers, a first elastic member, and second elastic members.

A paper conveying device includes a support shaft configured to pivotally support a roll of paper having a center measured in a width direction, a guide movable in the width direction of the roll based on a size of the roll and configured to position the center of the roll in a reference position, and a sensor coupled to the guide and configured to detect that the roll contains less than a threshold amount of paper based on a diameter of the roll.

A telescopic pneumatic linear actuator, particularly for unwinders with movable arms, includes a first annular cylinder, provided with a respective cavity, and a second annular cylinder, which can be inserted into and can slide within the cavity of the first annular cylinder and is provided with a respective cavity. The actuator also includes an annular piston, which can be inserted into and can slide within the cavity of the second annular cylinder. The first and second annular cylinders and the annular piston are provided with respective holes for the passage of a self-expanding spindle.