An image forming apparatus includes a toner container, a first conveyance unit, and an apparatus main body. The apparatus main body includes a photosensitive drum, a development roller, a second conveyance unit, a toner conveyance passage, light sensor, an acquisition unit, and a control unit configured to execute an abnormality detection mode. In an abnormality detection mode, the acquisition unit acquires a first acquired value after the driving of the second conveyance unit with the driving of the first conveyance unit stopped. When the first acquired value satisfies a first condition, the acquisition unit further acquires a second acquired value after the driving of the second conveyance unit with the driving of the first conveyance unit stopped. The apparatus main body further includes a notification unit to make notification of the abnormality when the second acquired value satisfies a second condition.

An image forming apparatus, including: a photoconductor; a developing device; a developer storage; a supplier configured to supply developer; an optical sensor; and a controller configured to execute: a developing process of developing an electrostatic latent image on the photoconductor; a usage-amount obtaining process of obtaining a usage amount of the developer; a supplying process of supplying the developer to the developing device every time when the obtained usage amount becomes equal to or greater than a first threshold; and a detecting process of detecting, by the optical sensor, an amount of the developer in the developing device every time when the obtained usage amount becomes equal to or greater than a second threshold larger than the first threshold, and wherein the controller is configured to execute the detecting process in a period different from a period in which the developing process is being executed.

An apparatus includes an image bearing member, a developer container having a replenishment port, a developer bearing member, a detection portion configured to output remainder amount information corresponding to the amount of developer accommodated in the developer container, a notification portion capable of notifying a first state, and a second state, and a control portion. The maximum amount of the developer that the developer container is capable of accommodating is larger than a value obtained by adding the amount of the developer accommodated in a replenishment container containing the developer for replenishment to the first amount, and wherein notification of the second state corresponds to notification of a case where the amount of the developer remaining in the developer container is larger than a case where the amount of the developer remaining in the developer container is the smallest.

An image forming apparatus, including: a photoconductor; a developing device; a developer storage; a supplier configured to supply developer; an optical sensor; and a controller configured to execute: a developing process of developing an electrostatic latent image on the photoconductor; a usage-amount obtaining process of obtaining a usage amount of the developer; a supplying process of supplying the developer to the developing device every time when the obtained usage amount becomes equal to or greater than a first threshold; and a detecting process of detecting, by the optical sensor, an amount of the developer in the developing device every time when the obtained usage amount becomes equal to or greater than a second threshold larger than the first threshold, and wherein the controller is configured to execute the detecting process in a period different from a period in which the developing process is being executed.

An image forming apparatus includes a container and a detecting portion. The detecting portion includes a light emitting element, a light receiving element, and a light guiding portion. The light guiding portion includes first to fourth projected portions. An upper surface of the second projected portion is positioned above a first virtual rectilinear line along an upper surface of the first projected portion in a case where an upper surface of the second projected portion is viewed in a direction crossing both a first direction and a direction of gravitation. An upper surface of the third projected portion is positioned above a second virtual rectilinear line along an upper surface of the fourth projected portion as viewed in a direction crossing a second direction and the direction of gravitation.

An image forming apparatus includes (i) a housing including a first connector, (ii) a drum unit, (iii) a development unit including a containing portion containing toner and movable between an abutment position and a separation position, (iv) a detection unit including a light emitting element, a light receiving element, and a second connector electrically connected to the light emitting element and the light receiving element, and mounted on the development unit, and (v) a connection member connected to the first connector and the second connector to electrically connect the first connector and the second connector each. A length of the connection member is longer than a first distance from the first connector to the second connector when the development unit is located at the abutment position, and is longer than a second distance from the first connector to the second connector when the development unit is located at the separation position.

A toner amount detection sensor has a first light receiving element, a second light receiving element, and a toner amount calculation unit. The first light receiving element is provided on a side opposite to a light emitting element with respect to a plane extending in a direction perpendicular to a surface of a transfer belt. The second light receiving element is provided at a position avoiding a plane containing the light emitting element and the first light receiving element and is provided separately from the first light receiving element. The toner amount calculation unit calculates the toner amount from the light quantity of the light equivalent to the specular reflection light received by the first light receiving element and the light quantity of the diffuse-reflected light received by the second light receiving element.

A toner amount detection sensor has a substrate, and a case housing. In the substrate, the light emitting element, the first light receiving element, and the second light receiving element are attached with an interval to the same first surface. In the substrate, first and second slits and are provided between a region where the light emitting element is attached and regions where the first light receiving element and the second light receiving element are attached. In the case housing, first and second light shielding walls and are disposed in such a manner as to extend to reach the inside of the first and second slits and when attached to the substrate and first and second light shielding walls and are provided between the light emitting element and the first light receiving element and between the light emitting element and the second light receiving element.

A toner detection device includes sensor cases, optical sensors, a cleaning member, a motor, and a control unit. The sensor cases include detection surfaces and are placed on wall surfaces of a hopper container. The optical sensors are housed in the sensor cases and detect presence or absence of toner at a specified elevation through the detection surfaces. The cleaning member slides and rubs on the detection surfaces. The motor moves the cleaning member. In case where the cleaning member is to be stopped, the control unit controls the motor so as to stop the cleaning member in a region in which the cleaning member does not come into contact with the detection surfaces.

A powder detection device includes a detection unit, a cleaning unit, and a drive unit. The detection unit includes detection surfaces provided in a storage container and enables detection of powder through the detection surfaces. The cleaning unit removes the powder from the detection surfaces by sliding along the detection surfaces. The drive unit reciprocates the cleaning unit along a path extending through the detection surfaces and differentiates a speed at which the cleaning unit is moved in a first direction along the path from a speed at which the cleaning unit is moved in a second direction opposite to the first direction.