Apparatus and method for applying a liquid to a printing surface

An apparatus (100) for applying a liquid to a printing surface (150). The apparatus comprise: a housing (110) arranged to receive the liquid, the housing comprising an aperture and the aperture comprising at least a first side defined by the housing and a second side defined by the housing which is opposite to the first side, such that the liquid can flow out of the housing by passing through the aperture between the first side and the second side; and a liquid guide member (120) which is inserted into the aperture so that the liquid guide member extends from the first side to the second side. The liquid guide member comprises: a first transfer surface; a second transfer surface which is separated from the first transfer surface by a gap; a first channel which extends from a first inlet which is adjacent to the aperture to a first outlet which is adjacent to the first transfer surface; and a second channel which extends from a first inlet which is adjacent to the aperture to a first outlet which is adjacent to the second transfer surface, the liquid guide member being arranged such that in use the liquid will flow along the first channel from the aperture to the first transfer surface and then transfer from the first transfer surface onto the printing surface, and the liquid will flow along the second channel from the aperture to the second transfer surface and then transfer from the second transfer surface onto the printing surface as the printing surface moves relative to the apparatus.