A cleaning fluid for cleaning a site to which ink adheres in an inkjet printer which ejects aqueous inkjet ink containing a pigment and alkali-soluble resin having an acid group in a molecule, wherein the cleaning fluid contains an amphoteric surfactant, a basic compound, and water, a pH range of the cleaning fluid is from 9 to 12, the amphoteric surfactant is at least one selected from a group consisting of dimethyl_lauryl_amine oxide, lauryl_dimethyl_amino acetic acid betaine and a 2-al-kyl-n-carboxymethyl-n-hydroxyethyl_imidazolinium betaine and is contained in an amount of 0.1- to 3% by mass to the total amount of the cleaning fluid.

An ink composition for use in digital offset printing including at least one component selected from the group consisting of a curable monomer and a curable oligomer; an optional dispersant; an optional photoinitiator; and at least one non-radiation curable additive, wherein the non-radiation curable additive is a detergent or an emulsifying agent, or wherein the non-radiation curable additive functions as a detergent or emulsifying agent when in the presence of a cleaning fluid, and wherein the non-radiation curable additive is a solid at a temperature of from about 20° C. to about 40° C.

A cleaning unit includes a cleaning head that moves a cleaning member, which cleans the screen mask at the cleaning position, a cleaning member holder that supports a first shaft and a second shaft, over which the cleaning member is bridged, and has an opening section allowing the cleaning head to pass therethrough, a base section that detachably fixes the cleaning member holder at a fixing position, a holder moving section that moves the cleaning member holder between the fixing position of the base section and a replacing position where the cleaning member holder is detached from the base section and is unloaded to an outside, and a cleaning driving section that has a connecting section, which is connected and disconnected to and from the first shaft in the cleaning member holder, and drives the first shaft to wind.

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.

A roll of cleaning fabric is used for cleaning printing cylinders of a printing system. The cleaning fabric (13) is impregnated with a cleaning composition containing an organic solvent and a cellulose solubilizer. The roll may be wound around a core (14) and inserted in a removable sealing bag (15) configured to seal around the roll (12) of cleaning fabric (13) in order to prevent the cleaning composition from evaporating before use.

A cleaning unit includes a cleaning head that moves a cleaning member, which cleans the screen mask at the cleaning position, a cleaning member holder that supports a first shaft and a second shaft, over which the cleaning member is bridged, and has an opening section allowing the cleaning head to pass therethrough, a base section that detachably fixes the cleaning member holder at a fixing position, a holder moving section that moves the cleaning member holder between the fixing position of the base section and a replacing position where the cleaning member holder is detached from the base section and is unloaded to an outside, and a cleaning driving section that has a connecting section, which is connected and disconnected to and from the first shaft in the cleaning member holder, and drives the first shaft to wind.

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.

A variable lithographic cleaning apparatus, system and method works on the principle that dust and ink residue may be transferred from a lower surface energy reimageable conformable blanket surface to a higher surface energy surface low durometer cleaning member, such as the tacky roller, and then to an even higher surface energy cleaning member, such as the hard roller, which is hard and robust to scratching. The hard roller can then been scrubbed clean by an ink flushing device having a third cleaning member, such as a melamine sponge, wetted with a cleaning solution with the hard roller dried upon each rotation.

An ink composition for use in digital offset printing including at least one component selected from the group consisting of a curable monomer and a curable oligomer; an optional dispersant; an optional photoinitiator; and at least one non-radiation curable additive, wherein the non-radiation curable additive is a detergent or an emulsifying agent, or wherein the non-radiation curable additive functions as a detergent or emulsifying agent when in the presence of a cleaning fluid, and wherein the non-radiation curable additive is a solid at a temperature of from about 20 C. to about 40 C.

A dampening fluid useful in offset ink printing applications contains water and a surfactant whose structure can be altered. The alteration in structure aids in reducing accumulation of the surfactant on the surface of an imaging member. The surfactant can be decomposed, switched between cis-trans states, or polymerizable with ink that is subsequently placed on the surface.