Sharp Kabushiki Kaisha Corporation

Takeshi Ohkawa

Kiyofumi Morimoto

Motoyuki Itoyama

Mitsuru Tokuyama

Masayasu Narimatsu

Kazuma Hinoue

Kohichi Takenouchi

Tomoki Minamikawa

Hideji Saikoh

Takahiro Bito

Tatsuo Imafuku

Takeshi Satoh

Yuichiro Takesue

Eiji Tenjiku

Akiko Tsujimoto

A developing apparatus including a layer thickness adjustment member configured to regulate a layer thickness of a two-component developer carried on a surface of a developing sleeve of a developing roller is disposed so that one end portion in a width direction faces the surface of the developing sleeve at a predetermined interval. At two end portions in a longitudinal direction of the layer thickness adjustment member, a notch open to the one end side in the width direction is provided. Since an amount of conveyance of the developer locally increases at two end portions of the developing sleeve by providing such a notch in the layer thickness adjustment member, density of an ear of a magnetic brush to be formed increases, and it is possible to exhibit the sufficient seal performance and prevent the toner from being scattered.

Developing apparatus and image forming apparatus

An image forming apparatus includes: a developing device having a developing vessel, a developing roller and a toner supply port; a toner supply device; a toner supply detecting sensor for detecting the toner concentration inside the developing vessel; a toner concentration controller for directing toner supply; a toner empty detector; and a sheet conveyance detecting sensor. The toner concentration controller has a toner supply device control function; and a toner supply stopping function of stopping toner supply when the last sheet of image printout being executed has passed by the predetermined position in the sheet conveyance path.

Image forming apparatus and image forming method

An image forming apparatus prevents printed images from being degraded in image quality due to failure of the toner concentration to fall within a proper range, by correcting the deviations of the amount of toner consumption and the amount of toner supply depending on the individuality of each image forming apparatus and that enables exact identification of the cause of a fault associated with toner concentration, and providing an image forming method using the apparatus. A toner supply device supplies toner to a developing vessel through an opening in accordance with an instruction from a controller. The presence or absence of toner falling is detected based on the variation of the output from a magnetic permeability sensor when toner is supplied. The controller monitors the output voltage level of the magnetic permeability sensor and adjusts the input gain in accordance with the output voltage level to thereby control toner concentration.

Image forming apparatus and image forming method using the same

An image forming apparatus includes: a developing device; a toner supply device; and a toner supply detecting sensor; and a toner concentration controller that directs toner supply. The toner concentration controller includes: a memory that stores the difference between the outputs from toner supply detecting sensor before and after toner supply; a toner supply quantity determinater that determines that the amount of toner remaining in the toner supply device is low and the amount of toner supply is low when the output difference or output ratio of the sensor is lower than a supply reference value; and an image quality adjustment controller that shortens the interval of time between adjustment of electrical potential on toner concentration correction in the above case.

Toner concentration controller and image forming apparatus including the toner concentration controller

An image forming apparatus includes a developing device having a toner supply sensor, a toner supply device supplying toner to the developing device, a toner supply controller controlling toner supply from the toner supply device to the developing device based on predetermined conditions, a toner empty determiner determining whether toner is present inside the toner supply device. In the image forming apparatus, the toner supply device includes a storage for recording multiple measured values of toner supply detected by the toner supply sensor, and the toner supply controller corrects the amount of toner supply, based on the moving average of multiple measured values of the amount of toner supply.

Image forming apparatus and toner supply method

A developing device includes a developer tank for housing a two-component developer containing toner and magnetic carrier; a first conveying portion having a first rotary shaft rotatable about its axis and a first screw blade which surrounds the first rotary shaft and rotates together with the first rotary shaft and contains a ferromagnetic substance; a second conveying portion having a second rotary shaft rotatable about its axis and a second screw blade which surrounds the second rotary shaft and rotates together with the second rotary shaft and contains a ferromagnetic substance; a first electromagnet for magnetizing the first screw blade; and a second electromagnet for magnetizing the second screw blade.

Developing device, image forming apparatus, and cleaning method for the developing device

A toner cartridge is a developer storage container for storing toner (developer) in a hollow cylindrical section that is driven to rotate on its axis so that the stored toner is discharged from an outlet. The cylindrical section has an inner circumferential surface provided with a plurality of liner protruding portions that extend in a direction tilted with respect to a rotation direction of the cylindrical section. Moreover, the toner cartridge includes a stirring member capable of moving in the cylindrical section so as to collide with the protruding portions. This makes it possible to stably supply a developer and to realize an inexpensive developer storage container whose size can be reduced.

Developer storage container and image forming apparatus

A toner for electrostatic image development, which contains toner particles in which not more than 13 percent by number of the toner particles have a particle diameter of smaller than 4 &#x3bc;m, not less than 20 percent by number of the toner particles have a particle diameter of 4 &#x3bc;m to 6 &#x3bc;m, and not more than 2.0 percent by volume of the toner particles have a particle diameter of 16 &#x3bc;m or greater. The toner particles have a volume average diameter of 4 &#x3bc;m to 9 &#x3bc;m, and at least an external additive is added to the toner particles.

Growing community of inventors

Osaka, Japan

Takeshi Ohkawa