Abstract: A developing unit is disclosed that includes a sub rotary developing unit, a toner supply device, and a drive device. The sub rotary developing unit has a developing roller in the interior thereof, and an elastic seal made of an elastic member with a slit sealing an opening on the sub rotary developing unit. The toner supply device supplies toner from a nozzle at the tip thereof to the sub rotary developing unit. The drive device drives the tip of the nozzle of the toner supply device into the sub rotary developing unit through the slit on the elastic seal in order for the toner supply device to supply toner into the sub rotary developing unit, and pulls the tip away when toner is properly supplied.

Abstract: A developing device includes a toner container, a developer carrier, end-portion sealing parts, and a regulating member. The toner container is disposed to be adjacent to the image carrier, and has an opening. The developer carrier is rotatably supported by the toner container so that a part of the developer carrier is exposed to the outside from the opening, and provides the image carrier with toner. The end-portion sealing parts are disposed in the axial end portions of the opening, and prevent toner leaking from the toner container. The regulating member regulates the amount of toner on the developer carrier while the tip side contacts the surface of the developer carrier, and tip edges of axial end portions of the regulating member contact the surface of the developer carrier while the axial end portions are pressed to the surface of the developer carrier by the end-portion sealing parts.

Abstract: An image forming device is disclosed, and includes a photosensitive drum, a laser unit for irradiating the photosensitive drum with laser light, developing units for developing the electrostatic latent image on the surface of the photosensitive drum, a toner container for containing toner to be supplied to the developing device, and toner supply pipes located so as to be movable between a supply position for supplying the developing units with the toner in the toner container, and a retracted position apart from the developing units. The toner supply pipes are located in a laser light path of the laser unit in the supply position, and are located so as to allow the laser light from the laser unit to reach the photosensitive drum in the retracted position.

Abstract: A toner supply device is disclosed that supplies toner contained in a toner container to a developing device in an image forming device. The toner supply device includes a conveyance pipe for conveying the toner from the toner container to the developing device downward, and at least one supply pipe for supplying the toner from the conveyance pipe to the developing device downward. The conveyance pipe is connected to the toner container for conveying the toner from the toner container to the developing device. The supply pipe has an upper portion connected to the conveyance pipe and a lower end capable of advancing into the developing device. In addition, a conveyance member is rotatably located in the supply pipe for conveying the toner downward. The supply pipe is located such that a center axis of the supply pipe is slanted relative to the horizontal line at a repose angle of the toner or more.

Abstract: A developing unit is disclosed that includes a sub rotary developing unit, a toner supply device, and a drive device. The sub rotary developing unit has a developing roller in the interior thereof, and an elastic seal made of an elastic member with a slit sealing an opening on the sub rotary developing unit. The toner supply device supplies toner from a nozzle at the tip thereof to the sub rotary developing unit. The drive device drives the tip of the nozzle of the toner supply device into the sub rotary developing unit through the slit on the elastic seal in order for the toner supply device to supply toner into the sub rotary developing unit, and pulls the tip away when toner is properly supplied.

Abstract: A full color image developing device for a color printer is disclosed, in which a black developing unit employs a magnetic one-component developing system, and color developing units (except for black) employ a non-magnetic one-component toner. The diameters of the non-magnetic developing rollers are set smaller than those of the magnetic developing roller. This configuration makes it possible to extend the lifespan of the color printer as well as reduce the size and cost thereof.

Abstract: An image forming device is disclosed, and includes a photosensitive drum, a laser unit for irradiating the photosensitive drum with laser light, developing units for developing the electrostatic latent image on the surface of the photosensitive drum, a toner container for containing toner to be supplied to the developing device, and toner supply pipes located so as to be movable between a supply position for supplying the developing units with the toner in the toner container, and a retracted position apart from the developing units. The toner supply pipes are located in a laser light path of the laser unit in the supply position, and are located so as to allow the laser light from the laser unit to reach the photosensitive drum in the retracted position.

Abstract: A toner supply device is disclosed that supplies toner contained in a toner container to a developing device in an image forming device. The toner supply device includes a conveyance pipe for conveying the toner from the toner container to the developing device downward, and at least one supply pipe for supplying the toner from the conveyance pipe to the developing device downward. The conveyance pipe is connected to the toner container for conveying the toner from the toner container to the developing device. The supply pipe has an upper portion connected to the conveyance pipe and a lower end capable of advancing into the developing device. In addition, a conveyance member is rotatably located in the supply pipe for conveying the toner downward. The supply pipe is located such that a center axis of the supply pipe is slanted relative to the horizontal line at a repose angle of the toner or more.

Abstract: An apparatus for controlling toner concentration includes a toner concentration detector, a toner supplier, a wave-former that periodically scrapes off toner from a detecting face of the toner concentration detector and thereby forms a wave of decreasing output of the toner concentration detector, and an about-minimum value detector that detects a minimum of the decreasing output. A toner concentration detection retarder is actuated from the time the minimum is detected. The toner supplier is actuated based on the detected toner concentration after the toner concentration detection retarder is released of action.

Abstract: The present invention provides a toner concentration control device which can measure the concentration of toner stably in an extended period of time without influenced by the shape of a developer stirring mixer rib and mounting position of a toner concentration detecting censer, with a result the stagnation or adhesion of toner in the proximity of the toner concentration detecting censer is eliminated, by so composing a toner concentration control device having a toner concentration censer for detecting magnetically the concentration of toner mounted facing a developer stirring mixer in a developing vessel, so that a waveform detection means which detects the output of the toner concentration censer for at least over one cycle before a toner supply means is activated, and an about-minimum value judging means which judges the minimum value or its vicinity detected by the waveform detection means are provided, and an about-minimum detection means is activated on the basis of the value judged as minimum or its