Abstract: A development device includes a developer housing, a toner concentration detection sensor, and a cover member. The developer housing stores a developer containing toner and a carrier. The toner concentration detection sensor is attached to a lower surface of the developer housing and is configured to detect a toner concentration of the developer stored in the developer housing. The cover member is attached to the lower surface of the developer housing to cover the toner concentration detection sensor. The cover member includes a pressing section for pressing a part of the toner concentration detection sensor against the lower surface of the developer housing.

Abstract: An image forming device includes a toner cartridge which is housed in a cartridge housing portion, and a pushing-out unit, and the toner cartridge includes a CRUM chip. The CRUM chip stores specific information about whether the toner cartridge can be extracted at a housed position where the toner cartridge is housed in the cartridge housing portion. The pushing-out unit pushes-out the toner cartridge in a direction that the toner cartridge can be extracted from the cartridge housing portion in a case where the specific information indicates that the toner cartridge cannot be extracted at the housed position.

Abstract: A development device includes a developer housing, a toner concentration detection sensor, and a cover member. The developer housing stores a developer containing toner and a carrier. The toner concentration detection sensor is attached to a lower surface of the developer housing and is configured to detect a toner concentration of the developer stored in the developer housing. The cover member is attached to the lower surface of the developer housing to cover the toner concentration detection sensor. The cover member includes a pressing section for pressing a part of the toner concentration detection sensor against the lower surface of the developer housing.

Abstract: An image forming device includes a toner cartridge, and the toner cartridge includes a CRUM chip. The CRUM chip stores specific information about whether an ejection action by an ejection mechanism for the toner cartridge is permitted. In accordance with an instruction by a control portion of the image forming device, the ejection action is permitted in a case of a permitting cartridge for which the ejection action is permitted, and the ejection action is inhibited in a case of an inhibiting cartridge for which the ejection action is inhibited.

Abstract: An image forming device includes a toner cartridge, and the toner cartridge includes a CRUM chip. The CRUM chip stores specific information about whether an ejection action by an ejection mechanism for the toner cartridge is permitted. In accordance with an instruction by a control portion of the image forming device, the ejection action is permitted in a case of a permitting cartridge for which the ejection action is permitted, and the ejection action is inhibited in a case of an inhibiting cartridge for which the ejection action is inhibited.

Abstract: An image forming device includes a toner cartridge, and the toner cartridge includes a CRUM chip. The CRUM chip stores specific information about whether an ejection action by an ejection mechanism for the toner cartridge is permitted. In accordance with an instruction by a control portion of the image forming device, the ejection action is permitted in a case of a permitting cartridge for which the ejection action is permitted, and the ejection action is inhibited in a case of an inhibiting cartridge for which the ejection action is inhibited.

Abstract: Disclosed is a corona charging apparatus for electrically charging a surface of an image bearing member to which the corona charging apparatus faces and which is rotatably provided in an electrophotographic image forming apparatus, the corona charging apparatus including: a discharging electrode; a shield case that covers the discharging electrode, the shield case being opened at least in a region where the discharging electrode and the image bearing member face each other; and a sheet-like member being made from aluminum and being attached to a first surface of the shield case which first surface faces the discharging electrode.

Abstract: A charging device is provided. A charging device includes a charging section and a discharge product adsorption removal section. The charging section includes a shield case having a shield opening, a discharge electrode, and a rotation shaft which is parallel to a rotation axis of a photoreceptor. The discharge product adsorption removal section has an adsorption layer that adsorbs a discharge product and is disposed downward in a vertical direction of the photoreceptor. The charging section is displaceable about an axial line of the rotation shaft from a position where the shield opening opposes to the photoreceptor to a position where the shield opening opposes to the discharge product adsorption removal section.

Abstract: The change in an output voltage when a control voltage is changed is calculated, and the change in the control voltage divided by the calculated change in the output voltage is defined as a sensitivity coefficient. The sensitivity coefficient is recalculated for each predetermined time interval or whenever a predetermined condition is satisfied, and the control voltage is corrected based on the recalculated sensitivity coefficient. Example of the predetermined condition include the time of start-up of the apparatus, the time at which the accumulated number of printed sheets reaches a predetermined number, and the time of carrying out process control.

Abstract: Disclosed is a corona charging apparatus for electrically charging a surface of an image bearing member to which the corona charging apparatus faces and which is rotatably provided in an electrophotographic image forming apparatus, the corona charging apparatus including: a discharging electrode; a shield case that covers the discharging electrode, the shield case being opened at least in a region where the discharging electrode and the image bearing member face each other; and a sheet-like member being made from aluminum and being attached to a first surface of the shield case which first surface faces the discharging electrode.

Abstract: 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.

Abstract: In an image forming apparatus comprising a charging section, an exposure section, a developing section, a transfer section, a peeling section, a cleaning section including a cleaning blade, and a fixing section, the cleaning blade is composed by dispersing 15 parts by weight through 33 parts by weight of fluorine resin particulate and secondary particles thereof into 100 parts by weight of a synthetic resin of a base material and, on a surface of the cleaning blade 16a, and a number of the secondary particles of the fluorine resin particulate having a particle diameter of 0.5 ?m or more existing in unit area of 100 ?m2 is made to be 50 or less.

Abstract: A charging device is provided. A charging device includes a charging section and a discharge product adsorption removal section. The charging section includes a shield case having a shield opening, a discharge electrode, and a rotation shaft which is parallel to a rotation axis of a photoreceptor. The discharge product adsorption removal section has an adsorption layer that adsorbs a discharge product and is disposed downward in a vertical direction of the photoreceptor. The charging section is displaceable about an axial line of the rotation shaft from a position where the shield opening opposes to the photoreceptor to a position where the shield opening opposes to the discharge product adsorption removal section.

Abstract: An image forming apparatus includes a toner image forming section including a developing device having a developer tank for storing a two-component developer, a transfer section, a fixing section, a recording medium feeding section, and a discharging section. The image forming apparatus further includes a toner concentration detecting section for detecting the toner concentration in the developer tank, a printing speed switching section, a toner concentration calculating section for correcting a detection result obtained by the toner concentration detecting section according to a speed of printing to calculate the toner concentration, and a toner replenishment control section for replenishing the toner into the developer tank according to a calculation result by the toner concentration calculating section.

Abstract: 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.

Abstract: 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 mod

Abstract: 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.

Abstract: An image forming apparatus of the present invention includes main control section for controlling the charging control section and the development bias control section so that a potential difference between the photoconductor potential and the development bias potential in developer discharge from the development section is smaller than that in the image forming. Therefore, even when an amount of developer in the development section decreases due to developer discharge, increase of beads-carry-over onto the photoconductor from the development section can be prevented. Accordingly, damage to the photoconductor or image errors due to incomplete cleaning that are caused by beads-carry-over can be prevented.

Abstract: 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.

Abstract: 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.