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 developing device includes a developing container, first and second stirring-conveyance members, a developer carrier, a toner concentration sensor, a scraper, and a scraper attachment unit. The second stirring-conveyance member includes a rotation shaft, a first spiral blade to convey developer in an axial direction, and a second spiral blade to overlap a region where the first spiral blade is formed, which is opposite to the first spiral blade in phase, and lower than the first spiral blade in height in a radial direction. An absent region, where the second spiral blade does not exist, is formed in one pitch of the first spiral blade, the one pitch facing the toner concentration sensor. The scraper attachment unit is formed to extend, along a straight line passing through intersection points of the first and second spiral blades and parallel to the rotation shaft, into the absent region.

Provided is an image forming apparatus, which is configured to determine that a toner container was replaced during power off in a case where identification information acquired from a toner container and identification information stored in a nonvolatile memory do not match each other when power is turned on. In a case where the replaced toner container does not satisfy a replacement condition and does not contain a black toner, the image forming apparatus permits the execution of printing in a monochrome print mode, and suspends the execution of printing in the color print mode.

Each of the oscillation frequency of a first oscillation circuit performing oscillation in a state of including a coil and a capacitor and the oscillation frequency of a second oscillation circuit performing oscillation in a state of including a coil and a capacitor different from the coil and the capacitor of the first oscillation circuit is measured. Then, the difference of the measured oscillation frequencies is calculated and then the calculated difference is converted into a magnetic permeability or a dielectric permittivity. One sensor selectively detects a change in the magnetic permeability or a change in the dielectric permittivity of a subject material.

An image forming apparatus determines a toner density erroneous detection state based on a patch image density in patch detection auto toner replenishing and, when the toner density erroneous detection state is determined, offsets a target toner density by the amount of erroneous detection so that the actual toner density becomes a desired toner density.

A developing apparatus includes a developer bearing member configured to bear and convey a developer containing toner and carrier, a first conveyance screw arranged in a first chamber to convey the developer, a second conveyance screw arranged in the second chamber to convey the developer, and a permeability sensor configured to detect a permeability of the developer. A detection portion of the sensor is arranged below a rotational axis of the second conveyance screw, and a rib portion is formed so as to protrude in a radial direction from a rotation shaft of the second conveyance screw for supplying the developer toward the detection portion.

The technology described herein relates to double-stranded ribonucleic acid (dsRNA) compositions targeting the Serpina1 gene, and methods of using such dsRNA compositions to inhibit expression of Serpina1.

An image forming apparatus includes a developing device, an image bearing member, an image density detecting portion, a toner content detecting portion, a humidity sensor, a supplying portion, and a controller configured to control the supplying portion so that a toner content is between an upper limit and a lower limit thereof. The controller can execute setting control in which the target value of the toner content is set on the basis of an image density of a reference toner image. The controller sets the lower limit until execution of subsequent setting control, wherein the lower limit is higher when a humidity is a first humidity and an average image ratio is a first ratio than when the humidity is a second humidity higher than the first humidity and the average image ratio is a second ratio larger than the first ratio.

A developing device includes a rotatable developer carrying member, first and second chambers configured to accommodate developer supplied to the developer carrying member, and first and second rotatable feeding members provided in the first and second chambers, respectively. A first communication port permits feeding of the developer from the second chamber to the first chamber, and a second communication port permits feeding of the developer from the first chamber to the second chamber. In addition, a toner content detecting portion includes a planar detecting surface including at least a planar coil generating a magnetic field and detects the toner content. The detecting surface is provided in the first communication port above a bottom of the first communication port and is disposed substantially in a central portion of the first communication port.

An image forming apparatus includes: an image carrier that carries an image; a transport-path forming part that forms a transport path for developer used to develop the image carried by the image carrier; a transport member that transports the developer in the transport path; and a concentration detector that detects toner concentration in the developer in the transport path. The transport path includes a first portion and a second portion. Difference in sectional area between the second portion and the transport member in a direction intersecting a direction in which the developer is transported is smaller than difference in sectional area between the first portion and the transport member. The second portion is located downstream of the first portion in the direction in which the developer is transported. The concentration detector is disposed in the second position of the transport path.