Surface-potential distribution measuring apparatus, image carrier, and image forming apparatus

A surface-potential distribution measuring apparatus that measures a potential distribution of a latent image on a surface of a sample by scanning the surface with a beam of charged particles, the surface-potential distribution measuring apparatus comprising:

• an image forming unit that forms the latent image on the surface of the sample by distributing a charge potential on the surface of the sample;
• a beam generating unit that generates a beam of charged particles;
• an optical system that is located between the beam generating unit and the sample, and focuses the beam from the beam generating unit to the surface of the sample;
• a particle emitting member that is located near the sample to be collided with at least part of the charged particles via the sample, and emits secondary charged particles corresponding to number of collided charged particles;
• a detecting unit that detects at least part of the secondary charged particles;
• and
• a calculating unit that calculates the potential distribution of a latent image pattern formed on the surface of the sample by the image forming unit based on a detection result obtained by the detecting unit.