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.

Date of Patent:
Jan. 09, 2018

Filed:

Mar. 21, 2016
Applicants:

Kenji Sengoku, Kanagawa, JP;

Hiromi Ogiyama, Tokyo, JP;

Hiroyoshi Haga, Kanagawa, JP;

Tomokazu Takeuchi, Tokyo, JP;

Yasunobu Shimizu, Kanagawa, JP;

Junpei Fujita, Kanagawa, JP;

Inventors:

Kenji Sengoku, Kanagawa, JP;

Hiromi Ogiyama, Tokyo, JP;

Hiroyoshi Haga, Kanagawa, JP;

Tomokazu Takeuchi, Tokyo, JP;

Yasunobu Shimizu, Kanagawa, JP;

Junpei Fujita, Kanagawa, JP;

Assignee:

Ricoh Company, Ltd., Tokyo, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03G 15/16 (2006.01); G03G 15/02 (2006.01); G03G 15/01 (2006.01);
U.S. Cl.
CPC ...
G03G 15/1665 (2013.01); G03G 15/0189 (2013.01); G03G 15/0266 (2013.01); G03G 2215/0129 (2013.01);
Abstract

An image forming apparatus includes an image bearing member to bear a toner image charged with a predetermined polarity, and a power source to apply a bias to a transfer portion to transfer the toner image from the image bearing member to a recording medium, a polarity of the bias being changed alternately. The toner image formed with toner of a plurality of colors is transferred in a color mode and the toner image formed with toner of a single color is transferred in a monochrome mode. The bias includes a peak voltage with a polarity that returns toner from the recording medium to the image bearing member. An absolute value of the peak voltage in the color mode is equal to or greater than an absolute value of the peak voltage in the monochrome mode.


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