Discharging light quantity adjusting device and image forming apparatus

A discharging light quantity adjusting device for adjusting a discharging light quantity to be irradiated by a discharging unit in an image forming section that performs a toner image forming process by charging, exposure and development to an image holding member, the image forming section comprising:

• the image holding member on which a toner image is formed while the image holding member rotates and which holds the formed toner image;
• a charging unit that electrically charges the image holding member;
• an exposure unit that exposes the image holding member to light so as to form a latent image by a potential distribution on the image holding member;
• a developing unit that develops the latent image formed on the image holding member by toner so as to form a toner image on the image holding member;
• a transfer unit that transfers the toner image formed on the image holding member onto a transfer object;
• the discharging unit that irradiates discharging light onto the image holding member so as to electrically discharge the image holding member;
• a cleaner that cleans toner remaining on the image holding member after the transferring;
• and an electrometer that measures an electrostatic potential on the image holding member,
• wherein the discharging light quantity adjusting device comprises:
• a potential measurement controller that performs:
• a first process of causing the image forming section to perform a first toner image forming process to electrically charge the image holding member to a first target potential, and causing the electrometer to measure an electrostatic potential on the image holding member so as to obtain a first measured value,
• a second process of causing the image forming section to perform a second toner image forming process to electrically charge the image holding member to a second target potential different from the first target potential and removing, from the image holding member, a toner image formed on the image holding member by the second toner image forming process, and
• a third process of causing the image forming section to perform a third toner image forming process to electrically charge the image holding member to a third target potential and causing the electrometer to measure an electrostatic potential on the image holding member so as to obtain a second measured value;
• and
• a light quantity adjusting unit that adjusts a quantity of the discharging light to be irradiated by the discharging unit based on the first and second measured values.