Sharp Kabushiki Kaisha Corporation

Takashi Gotoh

Hisashi Yoshimura

Hirokazu Nakamura

Masaki Matsushita

Naozumi Ueno

Hiroshi Ishii

Tomomi Tanaka

Akio Matsumoto

An image forming apparatus in which ink depletion detection accuracy will not be deteriorated even if an air bubble is created in an ink supplying path. The image forming apparatus is provided with (a) an ink storage section for storing ink therein, (b) an ink supplying path for supplying, to a print head, the ink stored in the ink storage section, and (c) an electrode for detecting whether the ink is present or absent in the ink supplying path, an amount of the ink supplied into the ink supplying path being 1.0 cc or less per minute.

Image forming apparatus

An image forming apparatus includes an ink tank; and an ink supplying path for supplying the ink from the ink tank to a print head, wherein the ink supplying path therein includes a filter, which generates negative pressure when the ink is supplied, the negative pressure being smaller than ink absorbing pressure of a nozzle of the print head. Further, the ink tank therein includes, for example, a porous ink absorbing body for retaining ink. The image forming apparatus satisfies:'&#x3c;1/() where F(m) expresses a filtration accuracy of the filter; N (cells/m) expresses a cell density of the ink absorbing body before the ink absorbing body is contained in the ink tank; and R expresses a compressibility, which is a volume ratio of the ink absorbing body when the ink absorbing body is contained in a compressed state in the ink tank to the ink absorbing body before the ink absorbing body is contained in the ink tank, on condition that: F&#x2032;=F when an opening of the filter is circle; F&#x2032;=&#x221a;{square root over ( )}2&#xb7;F in other cases.

Ink absorption pads are associated with waste ink storage apparatus in ink jet printers. Waste ink is emitted from the tubes. The waste ink is absorbed by the pads.

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Nara, Japan

Takashi Gotoh