Abstract: A doctor blade assembly adapted for applying liquid uniformly to a rotating transfer roller includes an applicator head having a channel-like cavity extending longitudinally parallel to the transfer roller axis. A pair of doctor blades extend obliquely from the longitudinal edges of the channel to impinge on the circumferential surface of the transfer roller. The blades each may be secured by longitudinally spaced screws, or by a blade holder secured to a longitudinal piano hinge and spring biased to clamp the respective blade. A pair of rotary end seals are joined to the opposed ends of the channel to form a sealed chamber against the transfer roller. Each end seal includes an end plate resiliently impinging on the end surface of the transfer roller, and a seal member secured to the end plate and disposed to engage the endmost portion of the circumferential roller surface. A plurality of mounting lugs extend outwardly from the applicator head, each lug including a stepped, semi-cylindrical portion.