Patents by Inventor Kiichiro Shimizu

Kiichiro Shimizu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7809291
    Abstract: An image forming apparatus in which a predetermined image density can be obtained by correcting a toner density control target value without consuming toner. The output value Vt of the magnetic permeability sensor and the target output value Vtref are compared, and the toner density is controlled by controlling a powder pump on the basis of the comparative result thereof so that the output value Vt approximates the target output value Vtref. In addition, the target output value Vtref is corrected on the basis of the detected result of the image coverage ratio so as to maintain a predetermined development potential of the development apparatus. By virtue of this, even when image forming that involves a significant change in the toner replacement amount in the development apparatus is performed, for example, even when an image of high image coverage ratio is output, the toner density is adjusted to maintain the development capability at a constant, and a predetermined image density is ensured.
    Type: Grant
    Filed: November 10, 2006
    Date of Patent: October 5, 2010
    Assignee: Ricoh Company, Ltd.
    Inventors: Nobutaka Takeuchi, Shinji Kato, Shin Hasegawa, Kouta Fujimori, Kayoko Tanaka, Yushi Hirayama, Takashi Enami, Kazumi Kobayashi, Kiichiro Shimizu