Abstract: A method of cleaning a cylinder of a printing machine comprises the steps of pressing a cleaning cloth onto the outer peripheral surface of the cylinder while the cylinder is rotating; forwardly feeding the cleaning cloth so as to wipe off contaminant on the outer peripheral surface of the cylinder; and partially feeding backwardly the portion of the cleaning cloth which has been fed forwardly during the preceding cleaning operation, before the next cleaning operation is started, whereby the portion of the cleaning cloth is partially used again for the cleaning in the next cleaning operation.

Abstract: A plate mounting device for an imprinter has a magnetized outer surface, and an imprinter plate cylinder having one or a plurality of positioning pin holes provided near a portion near an end of a plate to be mounted on the imprinter plate cylinder. A ferromagnetic base plate is mounted on the imprinter plate cylinder. The ferromagnetic base plate has a plate face provided with pin through-holes which are brought into alignment with the positioning pin holes so as to position a plate. When the base plate is mounted on the imprinter plate cylinder, those of the positioning pin holes which are not used are filled with magnetic pins.

Abstract: A method of cleaning a cylinder of a printing machine comprises the steps of pressing a cleaning cloth onto the outer peripheral surface of the cylinder while the cylinder is rotating; forwardly feeding the cleaning cloth so as to wipe off contaminant on the outer peripheral surface of the cylinder; and partially feeding backwardly the portion of the cleaning cloth which has been fed forwardly during the preceding cleaning operation, before the next cleaning operation is started, whereby the portion of the cleaning cloth is partially used again for the cleaning in the next cleaning operation.

Abstract: A device for cleaning a cylinder of a printing machine of the type which uses a cleaning cloth stretched between a cloth supply roll and a cloth take-up roll and adapted to be brought into contact with the outer periphery of a cylinder in a printing machine by pressurizing means, the cleaning cloth being impregnated with a cleaning liquid before it is set in the device. Needing no cleasning liquid supply system or liquid supply control means, the device can be realized in a very simple and compact form, which allows for easy maintenance.

Abstract: A cylinder cleaning apparatus for cleaning the surface of a cylinder such as an impression cylinder of an offset printing machine having a projection such as paper grippers, by means of a cleaner unit with a cleaning cloth which is selectively held in pressure contact with the surface of the cylinder while the cylinder rotates so that the surface is cleaned, by the relative movement between the cleaner unit and the surface of the cylinder. The apparatus has a projection detector capable of detecting the projection on the cylinder, and a cleaner unit retracting mechanism operative in response to the output from the projection detector such as to retract the cleaner unit away from the surface of the cylinder when the projection is detected by the projection detector means, thereby enabling the cleaner unit to clear the projection.