Image forming apparatus which sets image forming condition based on calculated exposed area potential

摘要

An image forming apparatus includes a latent image bearer; a charger; an exposure device; a developing device; a potential detector to detect a surface potential at a detection position between an exposure position and a development position on the latent image bearer in a direction of rotation of the latent image bearer; and a potential controller to determine an image forming condition. The potential controller includes a potential calculator to calculate an exposed area potential based on a detected potential smaller in charging polarity than a potential threshold, out of the detected surface potential, and a threshold determiner to set the potential threshold between the exposed area potential and an unexposed area potential of the latent image bearer based on at least one of a change in the unexposed area potential, a change with time of the latent image bearer, and a change in an ambient condition.

主权项

1. An image forming apparatus comprising:
a latent image bearer; a charger to charge a surface of the latent image bearer; an exposure device to expose the surface of the charged latent image bearer according to image data to form an electrostatic latent image thereon; a developing device to supply toner to the electrostatic latent image on the latent image bearer to develop the electrostatic latent image; a potential detector to detect a surface potential at a detection position on the surface of the latent image bearer, the detection position disposed between an exposure position and a development position in a direction of rotation of the latent image bearer; and a potential controller to calculate an image forming condition, the potential controller including:
a threshold determiner to set a potential threshold to a value between an exposed area potential and an unexposed area potential, the unexposed area potential being a surface potential of an unexposed area of the latent image bearer after charging by the charger, based on at least one of a change in the unexposed area potential, a change with time of the latent image bearer, and a change in an ambient condition under which the image forming apparatus is used;a potential calculator to calculate the exposed area potential based on a potential which has been detected by the potential detector, the potential calculator using potentials which are smaller than an absolute value of the potential threshold; andan image forming condition calculator which sets an image forming condition using the exposed area potential which has been calculated, wherein the image forming device forms the images based on the image forming condition which has been set.