An image forming apparatus includes a density detecting portion configured to detect a density of a control toner image being formed every time when an image is formed on a predetermined number of sheets in successively forming the image on sheets, and a control portion configured to control an amount of supplying developer. The control portion controls forming of the control toner image so that the predetermined number of image-formed sheets is a first number in a period of time from when the use of a developing apparatus is started, until when an amount of developer of the developing apparatus reaches a set value which is larger than an amount of initial developer, and the predetermined number of image-formed sheets is a second number which is larger than the first number of image-formed images, after the amount of developer of the developing apparatus reaches the set value.

A toner level detection assembly for an electrophotographic image forming device according to one example embodiment includes a rotatable shaft is positioned within a toner reservoir. A magnet is connected to the shaft and is rotatable with the shaft around an axis of rotation of the shaft. The magnet is pivotable independent of the shaft about a pivot axis that is spaced radially from the axis of rotation such that a radial distance of the magnet from the axis of rotation varies as the magnet pivots about the pivot axis. A first magnetic sensor is positioned to sense the magnet within a first range of radial distances from the axis of rotation. A second magnetic sensor is positioned to sense the magnet within a second range of radial distances from the axis of rotation.

A powder detector includes a driver to drive a motor, a stirrer to stir powder in a vessel, a vibration plate disposed in the vessel and vibrated by a flip of the stirrer rotated by the motor, and circuitry. The circuitry detects a vibration of the vibration plate, estimates an amount of powder based on a detection result of the vibration, and causes the driver to drive the motor from a starting point, so as to move the stirrer to a preset halt position. The starting point is a rotation angle of the motor on detection of the vibration.

A powder supply device that includes a powder reservoir including a rotator having a rotation shaft, to store powder supplied from a powder container; and a powder amount detector. The powder amount detector includes a detected member disposed in the powder reservoir, a contact member attached to the rotation shaft, to contact the detected member to vibrate or move the detected member, a detector to detect vibration or a displacement of the detected member, and a detection result processor to detect the amount of the powder in the powder reservoir based on detection by the detector. The powder supply device further includes a controller to supply the powder from the powder container to the powder reservoir based on detection by the powder amount detector. The controller rotates the rotator in discharging the powder from the powder reservoir and supplying the powder from the powder container to the powder reservoir.

A developing device of an image forming apparatus includes a casing, two-component developer accommodated in the casing, and a stirring screw for conveying and stirring the developer in the casing by rotation in a predetermined direction. The image forming apparatus includes a toner concentration sensor that outputs a value indicative of the toner concentration of the developer in the casing. The image forming apparatus determines whether or not the developer in the casing has become uniform, based on the amount of change per unit time of the output value of the toner concentration sensor, acquired after the stirring of the developer in the casing by the stirring screw is started. It is possible to appropriately measure the reference value of the toner concentration.

A developer including developer particles. Each developer particle includes a binder resin, a brilliant pigment whose principal component is aluminum, a yellow pigment, a magenta pigment, a reddish-orange fluorescent dye, and a yellow fluorescent dye. When an average particle diameter of the brilliant pigments included in the developer particles is expressed as D (m), a number proportion of the developer particles having particle diameters in a range from 4 m to 1.2D m in the whole developer particles is less than or equal to 4%.

An image forming apparatus includes an image forming station configured to form a toner image on a recording material, a fixing portion configured to fix the toner image formed by the image forming station on the recording material, a selector configured to select a correction level for correcting a crease of an envelope by an operator, and a controller configured to control a fixing condition in response to the correction level selected on the selector.

An image forming apparatus includes an image forming station configured to form a toner image on a recording material, a fixing portion configured to fix the toner image formed by the image forming station on the recording material, a selector configured to select a correction level for correcting a crease of an envelope, by an operator, and a controller configured to control a fixing condition in response to the correction level selected on the selector.

A powder detection device includes a detection mechanism including an oscillation unit and a vibrated member, a vibrating member, and a detection unit. The oscillation unit outputs a signal having a frequency according to a state of a magnetic flux passing a space facing the oscillation unit. The vibrated member affecting the magnetic flux and disposed inside a container to face the oscillation unit via the container is vibrated by the vibrating member in a direction of facing the oscillation unit. The detection unit acquires frequency information of the signal at predetermined periods, determines presence/absence of an error of the detection mechanism based on error information associating a type of the error with a state of the signal, detects vibration of the vibrated member based on a change in the frequency information, and detects a remaining amount of powder in the container based on the detected vibration.

A powder conveying device includes a drop conveyance passage, an intersecting conveyance passage, a conveying screw, and a floating member. Powder entering from an inflow port drops in the drop conveyance passage. The intersecting conveyance passage communicates with a lower end of the drop conveyance passage and extends in an intersecting direction that intersects the drop conveyance passage. The conveying screw is disposed in the intersecting conveyance passage and rotates in a specified direction to convey the powder in the intersecting direction. The floating member is movably installed in the drop conveyance passage and floats in the drop conveyance passage to move by contact with the conveying screw. The inflow port and the floating member interfere with each other to prevent the floating member from coming out of the inflow port of the drop conveyance passage.