The invention provides a dyeing solution for lithographic printing plates and a dyeing method for waterless lithographic printing plates that show stable plate inspection characteristics with little decrease in dye concentration and less dyeing unevenness even when used for bulk plate processing. The dyeing method for waterless lithographic printing plates is designed so that when used to dye an image area formed on a waterless lithographic printing plate with a dyeing solution containing an organic solvent, the relation of |β−α|<5 (cal/cm.sup.3).sup.1/2 is held wherein β is the SP value of the polymer compound included in the image area and α is the SP value of the organic solvent. The dyeing solution for lithographic printing plates contains (a) a dye, (b) a specific anionic surface active agent, and (c) an organic solvent containing at least one selected from ethers and alcohols.

The invention provides a dyeing solution for lithographic printing plates and a dyeing method for waterless lithographic printing plates that show stable plate inspection characteristics with little decrease in dye concentration and less dyeing unevenness even when used for bulk plate processing. The dyeing method for waterless lithographic printing plates is designed so that when used to dye an image area formed on a waterless lithographic printing plate with a dyeing solution containing an organic solvent, the relation of |β−α|<5 (cal/cm.sup.3).sup.1/2 is held wherein β is the SP value of the polymer compound included in the image area and α is the SP value of the organic solvent. The dyeing solution for lithographic printing plates contains (a) a dye, (b) a specific anionic surface active agent, and (c) an organic solvent containing at least one selected from ethers and alcohols.

The platemaking apparatus according to the present invention forms a pattern on an ink film-forming press plate that has a surface layer containing a stimulus-responsive compound whose physical property can reversibly change in response to an external stimulus. The platemaking apparatus includes: a first stimulator that applies, to a surface of the press plate, a first stimulus that changes the physical property of the surface from a first physical property to a second physical property to form the pattern, on the basis of image data; a second stimulator that applies, to the surface of the press plate, a second stimulus that changes the physical property of the surface from the second physical property to the first physical property, to erase the pattern; and a cleaning unit that removes an ink remained on the surface of the press plate.

A cleaning system is provided for a printing press recirculation system, in which the cleaning system generates a plurality of bubbles within a fountain solution of the printing press recirculation system. The cleaning system includes (i) a first composition comprising a solid blend including (a) a first alkaline cleaning agent having a first alkaline strength, (b) a detergent salt, (c) a non-foaming emulsifying agent, and (d) a second alkaline cleaning agent having a second alkaline strength, in which the first alkaline strength is greater than the second alkaline strength; (ii) a second composition comprising one or more organic acids. Also provided are methods of cleaning a printing press recirculation system.

An apparatus for preparing a relief plate precursor, such as a printing plate precursor, that has to be treated. The apparatus includes a transport bar provided with at least one penetration element, preferably a plurality of penetration elements; and a plate coupling station configured for coupling a relief plate precursor to the transport bar by causing a penetration by the at least one penetration element through an unperforated area near an edge of a relief plate precursor.

An apparatus for preparing a relief plate precursor, such as a printing plate precursor, that has to be treated. The apparatus includes a transport bar provided with at least one penetration element, preferably a plurality of penetration elements; and a plate coupling station configured for coupling a relief plate precursor to the transport bar by causing a penetration by the at least one penetration element through an unperforated area near an edge of a relief plate precursor.

A flexographic printing plate includes at least one halftone printing area with a plurality of halftone dots. A halftone dot of said plurality of halftone dots is shaped as a relief area. Said relief area includes a central portion and a surrounding portion. Said central portion has a central dot floor with a first pattern of a plurality of pins protruding upwardly from the central dot floor. Said surrounding portion protrudes upwardly from the central dot floor and has a top side including a second pattern of a plurality of recesses. The first pattern and second pattern are such that the surrounding portion can be distinguished from the central portion.

A printing intaglio (100A), (100B) is a printing intaglio for use in intaglio printing, the printing intaglio having a surface which has a plurality of first recessed portions (12) that form a pattern to be printed, wherein at least one of the plurality of first recessed portions has a plurality of minute recessed portions (16p) inside the first recessed portion, and when viewed in a direction normal to the surface of the printing intaglio, a two-dimensional size of the plurality of minute recessed portions is not less than 10 nm and less than 500 nm.

A flexographic printing plate includes at least one halftone printing area with a plurality of halftone dots. A halftone dot of said plurality of halftone dots is shaped as a relief area. Said relief area includes a central portion and a surrounding portion. Said central portion has a central dot floor with a first pattern of a plurality of pins protruding upwardly from the central dot floor. Said surrounding portion protrudes upwardly from the central dot floor and has a top side including a second pattern of a plurality of recesses. The first pattern and second pattern are such that the surrounding portion can be distinguished from the central portion.

The present disclosure relates to cleaning a surface in a printing device, wherein a steam guiding member directs a steam flow towards the surface; wherein the steam flow interacts with a substance on said surface to clean a portion of the surface.