The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 19, 1994
Filed:
Jul. 02, 1992
Yoshihiro Hattori, Toyokawa, JP;
Suguru Hamamichi, Toyokawa, JP;
Hideaki Kodama, Okazaki, JP;
Yoshikazu Naito, Toyokawa, JP;
Takeru Kinoshita, Toyokawa, JP;
Minolta Camera Kabushiki Kaisha, Osaka, JP;
Abstract
In an electrophotographic image forming apparatus, a charger sensitizes the photoconductor at a desired initial potential and the photoconductor is exposed to form an electrostatic latent image, which is developed by a developer to form a toner image. A gradation correction table on the relation of the input image signal to the exposure amount is provided in a memory, and it is amended by adding a common amendment value to the image density signal in the gradation correction table. The common amendment value is determined according to the density of a standard toner image. If a plurality of gradation correction tables are stored in a memory, one of them is selected according to the output voltage of the charger or the bias potential of the developer. The selected gradation correction table is amended according to the surface potential of the photoconductor, the temperature of the photoconductor or the humidity of the photoconductor. Alternately, the detection value of the surface potential, the temperature or the humidity may be used to select the gradation correction table. The gradation table may be amended according to the state of the photoconductor. The amplification factor of the exposure amount for the photoconductor can be changed according to the state of the photoconductor, the temperature or the humidity of the photoconductor. The bias voltage of the developer or the output voltage of the charger may also be changed according to the state of the photoconductor.