Abstract: There is disclosed a selective wetting apparatus comprising a roller rotatable about a roller axis and comprising a wettable roller surface; an applicator unit having a lip which extends parallel to the roller axis and is radially spaced apart from the roller surface by a gap, wherein the applicator unit is to convey liquid agent towards the roller so that the liquid agent forms a liquid bridge over the gap to wet a wetted axial portion of the roller surface; and a flow guide to direct a gas flow into a regulated axial portion of the gap to locally prevent formation of a liquid bridge, and thereby prevent wetting of a corresponding axial portion of the roller surface.

Abstract: There is disclosed apparatus for wetting a roller of a printing system comprising an applicator unit comprising a liquid agent chamber. Upper and lower walls extend from the liquid agent chamber to define a slit therebetween. The upper wall extends beyond a lip of the lower wall to a transfer lip. A flow restrictor is received in the slit to prevent flow of liquid agent to a respective portion of the transfer lip, thereby defining a restricted portion of the slit and an adjacent unrestricted portion of the slit. The flow restrictor fits in the restricted portion with a clearance that permits liquid agent flow at a reduced velocity relative flow through the unrestricted portion, such that liquid agent along the restricted portion is discharged from the lower wall. A method of installing a flow restrictor is also disclosed.

Abstract: According to some examples a substance displacement apparatus may comprise a gas ejection aperture and a deflector arm. The gas ejection aperture may be to direct gas towards a roller having a surface on which a substance is disposed. The deflector arm may be moveable between a first position in which gas is directed away from a target area on the surface of the roller, and a second position in which gas is directed towards the target area on the surface of the roller, thereby to displace at least some of the substance from the surface of the roller within the target area. A method and a print apparatus are also disclosed.

Abstract: According to some examples a substance displacement apparatus may comprise a gas ejection aperture and a deflector arm. The gas ejection aperture may be to direct gas towards a roller having a surface on which a substance is disposed. The deflector arm may be moveable between a first position in which gas is directed away from a target area on the surface of the roller, and a second position in which gas is directed towards the target area on the surface of the roller, thereby to displace at least some of the substance from the surface of the roller within the target area. A method and a print apparatus are also disclosed.

Abstract: There is disclosed apparatus for wetting a roller of a printing system comprising an applicator unit comprising a liquid agent chamber. Upper and lower walls extend from the liquid agent chamber to define a slit therebetween. The upper wall extends beyond a lip of the lower wall to a transfer lip. A flow restrictor is received in the slit to prevent flow of liquid agent to a respective portion of the transfer lip, thereby defining a restricted portion of the slit and an adjacent unrestricted portion of the slit. The flow restrictor fits in the restricted portion with a clearance that permits liquid agent flow at a reduced velocity relative flow through the unrestricted portion, such that liquid agent along the restricted portion is discharged from the lower wall. A method of installing a flow restrictor is also disclosed.

Abstract: The present disclosure relates to cleaning a surface in a printing device, wherein a guiding member directs a stream of cleaning fluid towards the surface; and at least one barrier unit to confine the stream of cleaning fluid to a portion of the surface, wherein the at least one barrier unit guides air to provide at least one air curtain confining said stream of cleaning fluid to the portion of the surface.

Abstract: 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.

Abstract: According to some examples a substance displacement apparatus may comprise a gas ejection aperture and a deflector arm. The gas ejection aperture may be to direct gas towards a roller having a surface on which a substance is disposed. The deflector arm may be moveable between a first position in which gas is directed away from a target area on the surface of the roller, and a second position in which gas is directed towards the target area on the surface of the roller, thereby to displace at least some of the substance from the surface of the roller within the target area. A method and a print apparatus are also disclosed.

Abstract: There is disclosed a selective wetting apparatus (2) comprising a roller (20) rotatable about a roller axis (24) and comprising a wettable roller surface (22); an applicator unit (10) having a lip (12) which extends parallel to the roller axis (24) and is radially spaced apart from the roller surface (22) by a gap (30), wherein the applicator unit (10) is to convey liquid agent (14) towards the roller (20) so that the liquid agent (14) forms a liquid bridge (32) over the gap (30) to wet a wettable axial portion of the roller surface (22); and a flow guide (50) to direct a gas flow (56) into a regulated axial portion of the gap (30) to locally prevent formation of a liquid bridge (32), and thereby prevent wetting of a corresponding axial portion of the roller surface (22).

Abstract: Certain examples of an apparatus, a printing system and a method are described that may be used for applying a fluid. In certain cases, an apparatus has a chamber arranged to receive fluid, the chamber being sealed at one or more ends by one or more respective end seals. In one case, at least one end seal is moveable along an axis of the chamber to adjust at least a volume of the chamber.

Abstract: Certain examples of apparatus for applying fluid in a printing system are described. The apparatus comprise a first chamber having a first aperture extending along a first axis, and a second chamber having a second aperture extending along a second axis, wherein the first axis is substantially parallel to the second axis. The second chamber is movable with respect to the first chamber. Also, methods for supplying a fluid, and printing systems are described.

Abstract: 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.

Abstract: Certain examples of an apparatus, a printing system and a method are described that may be used for applying a fluid. In certain cases, an apparatus has a chamber arranged to receive fluid, the chamber being sealed at one or more ends by one or more respective end seals. In one case, at least one end seal is moveable along an axis of the chamber to adjust at least a volume of the chamber.

Abstract: The present disclosure relates to cleaning a surface in a printing device, wherein a guiding member directs a stream of cleaning fluid towards the surface; and at least one barrier unit to confine the stream of cleaning fluid to a portion of the surface, wherein the at least one barrier unit guides air to provide at least one air curtain confining said stream of cleaning fluid to the portion of the surface.

Abstract: Certain examples of an apparatus, a printing system and a method are described that may be used for applying a fluid. In certain cases, an apparatus has a chamber arranged to receive fluid, the chamber being sealed at one or more ends by one or more respective end seals. In one case, at least one end seal is moveable along an axis of the chamber to adjust at least a volume of the chamber.

Abstract: Certain examples of apparatus for applying fluid in a printing system are described. The apparatus comprise a first chamber having a first aperture extending along a first axis, and a second chamber having a second aperture extending along a second axis, wherein the first axis is substantially parallel to the second axis. The second chamber is movable with respect to the first chamber. Also, methods for supplying a fluid, and printing systems are described.

Abstract: Apparatus to apply a fluid to a substrate, the apparatus includes a first roller to rotate about an axis and apply a fluid to a first side of the substrate. The first roller includes an outlet to provide gas to the substrate to guide the movement of the substrate subsequent to the application of fluid to the substrate.

Abstract: Certain examples of an apparatus, a printing system and a method are described that may be used for applying a fluid. In certain cases, an apparatus has a chamber arranged to receive fluid, the chamber being sealed at one or more ends by one or more respective end seals. In one case, at least one end seal is moveable along an axis of the chamber to adjust at least a volume of the chamber.

Abstract: Apparatus to apply a fluid to a substrate, the apparatus includes a first roller to rotate about an axis and apply a fluid to a first side of the substrate. The first roller includes an outlet to provide gas to the substrate to guide the movement of the substrate subsequent to the application of fluid to the substrate.