US Patent No. 9,280,113

IMAGE FORMING APPARATUS CAPABLE OF STABILIZING IMAGE DENSITY ON A SHORT-TERM AND LONG-TERM BASIS


Patent No. 9,280,113
Issue Date March 08, 2016
Title Image Forming Apparatus Capable Of Stabilizing Image Density On A Short-term And Long-term Basis
Inventorship Jun Hirabayashi, Yokohama (JP)
Assignee CANON KABUSHIKI KAISHA, Tokyo (JP)

Claim of US Patent No. 9,280,113

1. An image forming apparatus comprising:
a predicting unit configured to predict an amount of electrostatic charge of toner particles in a developer container;
a determining unit configured to determine an exposure condition based on the amount of electrostatic charge of the toner
particles predicted by the predicting unit;

a storage unit configured to store a gradation conversion table;
a converting unit configured to convert image data based on the gradation conversion table stored in the storing unit;
an image forming unit configured to form an image based on the converted image data converted by the converting unit, the
image forming unit having an image bearing member, an exposure unit configured to expose the image bearing member using light
according to the exposure condition determined by the determining unit to form an electrostatic latent image on the image
bearing member, and a development unit configured to develop the electrostatic latent image using toner particles;

a measuring unit configured to measure a pattern image formed by the image forming unit;
a controlling unit configured to control the converting unit to convert pattern image data based on the gradation conversion
table, control the exposure unit to expose the image bearing member based on the converted pattern image data using light
according to the exposure condition determined by the determining unit to form a pattern image, and control the measuring
unit to measure the pattern image; and

an updating unit configured to correct the gradation conversion table stored in the storage unit based on the measurement
result of the pattern image, and to update the gradation conversion table stored in the storage unit to the corrected gradation
conversion table.