An image-forming apparatus includes: a main body; a toner cartridge having a first opening; a process cartridge having a photosensitive drum and a second opening; a positioning part; a transfer unit; and an urging member. The toner cartridge and process cartridge are attachable to and detachable from the main body in an axial direction of the photosensitive drum. The positioning part and transfer unit are positioned above the process cartridge attached to the main body. The positioning part fixes the attached process cartridge in position relative to the main body. The urging member urges the attached process cartridge toward the positioning part and urges the process cartridge such that the toner can be supplied from the toner cartridge to the process cartridge through the first opening and the second opening when the toner cartridge and the process cartridge are attached to the main body.

An image forming apparatus is capable of being attached with a toner supply container. The toner supply container stores a toner that is to be supplied to a developing portion. An attachment location of the toner supply container isbelow a light scanning portion in a vertical direction.

A nozzle insertion member is in a powder container that includes a nozzle insertion opening into which a conveying nozzle is inserted. The nozzle insertion member includes an opening/closing structure to move to an opening position to open the nozzle insertion opening by being pressed by the inserted conveying nozzle, and to a closing position to close the nozzle insertion opening when the conveying nozzle is separated from the nozzle insertion member, and a seal arranged at the nozzle insertion opening and including a through hole into which the conveying nozzle is insertable. The opening/closing structure includes a front cylindrical portion to contact with an inner surface of the through hole, and a slide area formed on another side relative to the front cylindrical portion. W1<W4 is satisfied, where W1 is an inner diameter of the through hole, and W4 is an outer diameter of the slide area.

A heater includes a heat generating member in a first layer, a sensor that is in a second layer different from the first layer and configured to detect a temperature of the heat generating member, and a wiring pattern in one or more third layers between the first and second layers to supply power to the heat generating member.

A developing device includes: a case in which a hollow transporting path is formed; a transporting member configured to transport a developer in the transporting path; a support portion fixed to an end portion of the case by a fastening member to support the transporting member at an end portion of the transporting path; and a cooling unit fixed by being sandwiched between the support portion and the case.

An image forming apparatus is capable of performing a second image forming operation in which a peripheral velocity ratio of a developer bearing member to an image bearing member becomes greater than that in a first image forming operation, and in which a potential difference between a developing bias applied to the developer bearing member and a supply bias applied to a supply member becomes a potential difference at which a urging force causing a developer at the contact portion between the developer bearing member and the supply member to move from the supply member to the developer bearing member becomes smaller than that in the first image forming operation, or becomes a potential difference at which a urging force causing the developer to move from the developer bearing member to the supply member is generated.

An image forming apparatus includes an image forming portion, a belt unit including a cleaning unit and an opposing roller, and a swinging mechanism. The swinging mechanism includes a swingable member which is provided in a position different from a rotation center of the opposing roller while holding the opposing roller and the cleaning unit without changing a relative positional relationship between the opposing roller and the cleaning unit and which is swingable about a swing axis.

An image forming apparatus is capable of being attached with a toner supply container. The toner supply container stores a toner that is to be supplied to a developing portion. An attachment location of the toner supply container is below a light scanning portion in a vertical direction.

The powder container includes a container body containing a powder for image formation, the powder being to be supplied to a powder replenishing device; a conveyor configured to convey the powder from one end in a longitudinal direction to the other end at which a cylindrical container opening is formed, the conveyor being provided inside the container body; a gear configured to rotate the conveyor with an external driving force; a container cover configured to cover the gear, the container cover having a gear exposing hole for partially exposing a gear tooth; and a nozzle receiver configured to guide the conveying nozzle inside of the container body, the nozzle receiver being provided on the container opening. The container cover includes a container engaged portion provided outer than the tooth of the gear in a radial direction.

An image forming apparatus has an image carrier that carries a toner image; a transfer member that is opposed to the image carrier, a transfer voltage being applied to the transfer member so that the toner image is transferred from the image carrier to a print medium passing between the transfer member and the image carrier; a first voltage application device that applies the transfer voltage to the transfer member; a separation member to which a separation voltage is applied so that the print medium is separated from the image carrier; a second voltage application device that applies the separation voltage to the separation member; a sensing device that senses an image density of the toner image; and a control section that controls a magnitude of the separation voltage based upon the image density of the toner image.