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:
Jun. 02, 2020
Filed:
Aug. 15, 2019
Fuji Xerox Co., Ltd., Tokyo, JP;
Naoki Ota, Kanagawa, JP;
Teppei Yawada, Kanagawa, JP;
FUJI XEROX CO., LTD., Tokyo, JP;
Abstract
An image forming apparatus includes: an image holding member; a charging unit that charges a surface of the image holding member; an electrostatic image forming unit that forms an electrostatic image on the charged surface of the image holding member; a developing unit that houses an electrostatic image developer including a toner containing an external additive and develops the electrostatic image formed on the surface of the image holding member with the electrostatic image developer to thereby form a toner image; a transfer unit that transfers the toner image formed on the surface of the image holding member onto a surface of a recording medium directly or through an intermediate transfer body; and a fixing unit that fixes the toner image transferred onto the surface of the recording medium. The transfer unit includes a contact portion-forming member that comes into contact with the image holding member or the intermediate transfer body to form a contact portion and a transfer bias application unit that applies a transfer bias including a superimposed voltage to the contact portion. The superimposed voltage has two peak values and is composed of an AC voltage and a DC voltage. The AC voltage has a duty ratio D of less than 50% on a peak value side opposite to a peak value that causes the toner in the contact portion to move from the image holding member or the intermediate transfer body toward the contact portion-forming member. The DC voltage causes the electric potential of the contact portion-forming member to be shifted to the side opposite to the charge polarity of the toner such that the absolute value of the electric potential of the contact portion-forming member is larger than the absolute value of the electric potential of the image holding member or the intermediate transfer body. The toner satisfies the following formulas:(ln η(1)−ln η(2))/(1−2)≤−0.14;(ln η(2)−ln η(3))/(2−3)≥−0.15; and(ln η(1)−ln η(2))/(1−2)<(ln η(2)−ln η(3))/(2−3),