Abstract: An optical beam scanning apparatus comprises: an beam source emitting an optical beam; a deflector deflecting the optical beam around a center line with a deflection angle .theta. radians in a main scanning direction perpendicular to the center line at a constant angular velocity d.theta./dt; a lens system, having a focal length f in the main scanning direction, for focusing the optical beam on a recording plane perpendicular to the center line to form and scanning a beam spot on the recording plane at a constant speed in the main scanning direction, wherein the lens system refracts the optical beam from the deflection means such that the constant speed is larger than f.multidot.d.theta./dt. An emitting angle from the lens system is larger than the deflection angle by the deflector. The deflector comprises a polygon mirror unit. The lens system may have a function to compensate a surface inclination in the polygon mirror unit.

Abstract: A developing apparatus has a toner reservoir for holding a non-magnetic toner, a toner supply roller including a supply surface for receiving the toner from the toner reservoir and electrifying the toner thereon, an electrostatic latent image carrier including a curved or flat latent image surface on which a latent image formed by an electrostatic voltage distribution thereon is developed by the toner transferred from the supply surface, and a toner seal surface arranged adjacent to the toner supply roller to contact a remaining part of the toner on the supply surface after the latent image development so that the remaining part of the toner is taken into the toner reservoir. The respective frictional coefficients between the toner seal surface and the toner and between the toner particles are selected to prevent a disturbance of toner condition between the toner and the toner seal surface.