Abstract: A device is provided for use in covering a danger area on a roll changer that can carry at least one roll of material to be directed to a rotary, web-fed printing press. A cover is provided with a drive that can move the cover. A control unit is provided to control the drive for the cover. The cover is closed in a first operational state and is open in a second operational state. The roll of material, that is supported by the roll changer, has a first rotational speed or web speed when the cover is in the first, closed operational state. In the second, cover opened, operational state, the roll of material also has a second rotational or web speed which is greater than zero. A method for controlling a device on a roll changer is also disclosed.

Abstract: A device is provided for use in covering a danger area on a roll changer that can carry at least one roll of material to be directed to a rotary, web-fed printing press. A cover is provided with a drive that can move the cover. A control unit is provided to control the drive for the cover. The cover is closed in a first operational state and is open in a second operational state. The roll of material, that is supported by the roll changer, has a first rotational speed or web speed when the cover is in the first, closed operational state. In the second, cover opened, operational state, the roll of material also has a second rotational or web speed which is greater than zero. A method for controlling a device on a roll changer is also disclosed.

Abstract: In a method for detecting the position of a web supply roll, the actual lateral positions of the two lateral faces of the web roll are detected and are compared with reference values. The differences between the actual and the reference values are used to shift the web supply roll laterally until the actual values are the same as the reference values.