PURPOSE: To improve the quality of a recording image by considering a process for forming a latent image and the consistency of a developing process.

CONSTITUTION: A signal read from a CCD image pickup element 5 is processed by an image processing part 6, and an LD 71 is lighted according to a pulse width corresponding to an image density. The surface of an image carrier 8 is uniformly electrified to the low potential of ≤-500V by the electrode of an electrifier 9, the charge of a region irradiated with the spot light of the LD 71 is erased, and an electrostatic latent image is formed, and developed by a developing device 10. The rotational speed of the sleeve 24 of the developing device 10 is lower than that of a conventional device, and besides, electrification to a negative polarity by an alternating bias is carried out similarly to an electrification polarity. The toner of the developing device, whose mean grain diameter is 2W6μm, is preferable.