Patent application number | Description | Published |
20100074655 | DEVELOPING DEVICE AND IMAGE FORMING APPARATUS AND DEVELOPER CONVEYING METHOD USING THE SAME - To provide a developing device, which includes: a first conveying passage through which a developer including a toner and a magnetic carrier is conveyed; a first conveying member disposed in the first conveying passage for conveying the developer in a predetermined whilst agitating; a toner supply port for supplying toner into the first conveying passage; and a multiple number of electromagnets arranged in the upper part of the first conveying passage and on the downstream side of the toner supply port with respect to the developer's direction of conveyance for creating magnetic fields inside the first conveying passage along the developer's direction of conveyance, and which can improve agitation performance and conveying performance of the developer without extremely increasing stress acting on the developer, as well as providing an image forming apparatus and developer conveying method using the device. | 03-25-2010 |
20100104305 | IMAGE FORMING APPARATUS - A developing device conveys a two-component developer on a first route of circulation and a second route of circulation, and includes a guide plate and an electromagnet that are used for choosing, in accordance with toner densities detected by two toner density detecting sensors respectively provided in the two routes, whether toner supplied from a toner supply device is guided into the first or second route of circulation. This makes it possible to provide an image forming apparatus that, even in cases where a large amount of toner is consumed at one end of a developing roller along the axial direction in a developing device provided with one toner supply opening, can form an image free from nonuniformity in image density or photographic fogs that are caused by nonuniformity in toner density of a two-component developer. | 04-29-2010 |
20110058824 | IMAGE FORMING APPARATUS - An image forming apparatus includes: a developing device; a toner supply device that supplies toner to the developing device; a toner concentration controller that directs the toner supply device to perform toner supply to the developing device; and a toner empty determiner for determining that no toner is left in the toner supply device. The developing device includes a toner supply detecting sensor that detects whether toner is supplied from the toner supply device into the developer container, in the developer container. The toner concentration controller gives directions to perform the toner supply when the toner concentration of the developer in the developing device has become lower than a predetermined level. The toner empty determiner determines that the toner supply device has no toner left therein when no effect of the toner supply is detected by the toner supply detecting sensor after the toner supply is directed by the toner concentration controller. The toner supply detecting sensor is disposed in the preliminary agitating section. | 03-10-2011 |
20110123204 | IMAGE FORMING APPARATUS AND TONER SUPPLY METHOD - 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 recoding 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. | 05-26-2011 |
20110229156 | IMAGE FORMING APPARATUS - 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. | 09-22-2011 |
20110255888 | IMAGE FORMING APPARATUS AND IMAGE FORMING METHOD - 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. | 10-20-2011 |
Patent application number | Description | Published |
20090010662 | IMAGE FORMING APPARATUS - An image forming apparatus that includes: an image forming portion for forming an image in accordance with image data contained in an input command; and a controller for controlling the image forming portion, and is constructed such that the controller includes: a mode switch for switching the image forming portion from a standby mode in which image forming is instantly enabled into a power-saving mode in which power supply to the image forming portion is partially stopped when no subsequent command has been received after a predetermined period elapsed from when image forming portion was operated last; a mode restoring portion for restoring the image forming portion from power-saving mode to standby mode when a subsequent command is received; and an image quality controller for performing image quality control of the image every time a predetermined time elapsed from when the image forming portion was last operated, and the image quality controller starts execution of the image quality control before the mode restoring portion restores the image forming portion from the power-saving mode to the standby mode. | 01-08-2009 |
20090010683 | DEVELOPING DEVICE AND IMAGE FORMING APPARATUS - A developing device includes a developing roller and a blade. The developing roller includes: a developing sleeve which rotates while holding two-component developer composed of toner and magnetic carrier on the outer surface having a plurality of grooves extending in parallel to an axis of the rotation; and a magnetic member, provided inside the developing sleeve in such a manner as to be unrotatable, for attracting the two-component developer onto the outer surface of the developing sleeve. The blade is provided outside the rotating sleeve with a gap from the outer surface of the developing sleeve for scraping off a part of the two-component developer on the outer surface of the developing sleeve. Also, the magnetic member includes a magnet for controlling magnetic flux density in the gap to range from 70 mT to 150 mT. This allows preventing image degradation caused by generation of development memory. | 01-08-2009 |
20090129824 | TONER CARRYING DEVICE AND IMAGE FORMING APPARATUS - A toner carrying device includes a flexible sheet, and a sheet moving mechanism for allowing the flexible sheet to move back and forth by pulling the flexible sheet. In the flexible sheet, a toner passage hole for leaving a first opening section of a toner carrying pipe to open is provided. In a case where the toner passage hole is divided into first through three areas in such a manner that (i) the first area is provided on a side of one end of the flexible sheet in a direction orthogonal to a moving direction of the flexible sheet; (ii) the second area is provided on a side of the other end of the flexible sheet in the direction orthogonal to the moving direction; and (iii) the third area is provided between the first area and the second area, the third area extends broader in the moving direction than respective of the first and second areas. This allows the flexible sheet partially having the toner passage hole in its area to move smoothly. | 05-21-2009 |
20090175635 | IMAGE FORMING APPARATUS AND DRIVE CONTROL METHOD OF THE SAME - An image forming apparatus capable of performing monochrome printing and color printing in which all the developing units share a single development transformer is constructed such that at the time of monochrome printing the photoreceptor drums for colors are stopped rotating while all the developing units are constantly applied with a high voltage. Further, the cumulative operation time in which the black photoreceptor drum has been operated for monochrome printing is calculated so that the color-printing photoreceptor drums which are stopped during monochrome printing are rotationally driven by a predetermined angle when the cumulative operation time exceeds predetermined fixed time. Thus, the surface of each color-printing photoreceptor drum that is being worn is restored by making the fresh surface of the drum oppose the associated color developing unit, whereby it is possible to prevent occurrence of defects on the surface of each photoreceptor drum. | 07-09-2009 |