Patent ID: 7386260

Claim:
A liquid developing unit for supplying a liquid toner, comprising: a tank for containing a liquid toner; a pick-up roller having a circumferential surface which draws the liquid toner from the tank to adhere the liquid toner to the circumferential surface of the pick-up roller by rotating in a first rotation direction and which has spiral-shaped grooves formed thereon which are twisted in a first direction for guiding the drawn liquid toner in one direction of the axial direction; and an application roller disposed in parallel to the pick-up roller, having a circumferential surface in contact with the circumferential surface of the pick-up roller, and supplied with the liquid toner from the pick-up roller by rotating in a second rotation direction which is opposite to the first rotation direction of the pick-up roller, the circumferential surface of the application roller having spiral-shaped grooves formed thereon which are twisted in the first direction for guiding the liquid toner supplied from the pick-up roller in a direction opposite to the one direction along the axial direction.