IMAGE-FORMING APPARATUS AND CARTRIDGE

摘要

An image-forming apparatus and a cartridge which inhibit troubles attributable to toner particle size distribution or toner/photoreceptor matching, such as a white-background fouling, afterimage, scattering, streaks, blurring, and blind spots, and are satisfactory with respect to image quality, thin-line reproducibility, and cleanability. Even when applied to a high-speed printer, the apparatus and cartridge can prevent fouling and selective development in long-term use and can stably form high-resolution images. The image-forming apparatus has an electrophotographic photoreceptor which includes a photosensitive layer containing an oxytitanium phthalocyanine which has major diffraction peaks for a CuKa line at Bragg angles (2?) of 9.0° and 27.2° and has at least one major diffraction peak for the line in the range of from 9.3° to 9.8°. It employs a toner satisfying all of the following requirements: (1) the volume median diameter (Dv50) is 4.0-7.0 µm; (2) the average roundness is 0.93 or higher; and (3) the volume median diameter (Dv50) and the percentage by number of toner particles having a size of 2.00-3.56 µm (Dns) satisfy the relationship Dns=0.233EXP(17.3/Dv50).