An image forming apparatus includes a photoconductor, a charging roller for charging the photoconductor, a current sensor for detecting a value of current flowing through the photoconductor or the charging roller as a result of application of voltage to the charging roller, an acquisition sensor for acquiring an environment value representing an environment state inside the image forming apparatus, and a processor configured to estimate a film thickness of the photoconductor, based on a value of current detected by the current sensor when a state in which the environment value falls within a predetermined range continues for a predetermined time or longer.

The present disclosure provides a process cartridge and a potential detection part. The process cartridge includes a cartridge body, a photosensitive drum rotatably installed at the cartridge body, and a potential detection part configured to detect an electrical signal on the image-forming region. The potential detection part includes a detection starting portion and a detection ending portion; the detection starting portion and the detection ending portion respectively correspond to a detection starting position and a detection ending position of a detectable region of the potential detection part along a first direction; a maximum distance along the first direction between orthographic projections of the detection starting portion and the detection ending portion on the image-forming region is L1; a length of the image-forming region along the first direction is L2; the first direction is in parallel with an axis direction of the photosensitive drum; and L1/L2>?.

An image forming apparatus includes a rotary including a first developing roller, a second developing roller, a first storage frame, and a second storage frame, a body frame with an opening, a first toner cartridge, a second toner cartridge, a first support member which is configured to support the first toner cartridge, and a second support member which is configured to support the second toner cartridge. The first support member is movable with respect to the first storage frame such that the first toner cartridge moves from the first attached position to the first retracted position. The second support member is movable with respect to the second storage frame such that the second toner cartridge moves from the second attached position to the second retracted position.

An image forming apparatus includes a rotary configured to rotate and including a developing roller and a storage frame including a storage portion configured to store toner, a body frame with an opening, a toner cartridge which is attachable to and detachable from the rotary through the opening, which is movable to an attached position and a retracted position, a moving device configured to move the toner cartridge from the attached position to the retracted position, and an opening/closing member provided to be movable between a closed position and an open position. The opening/closing member is configured to move from the closed position to the open position in an interconnected manner with movement of the toner cartridge from the attached position to the retracted position by the moving device.

An image forming apparatus includes a developing device including a developing roller and a storage frame including a storage portion configured to store toner, a body frame with an opening, a toner cartridge which is configured to store the toner, which is attachable to and detachable from the developing device through the opening, which is movable to an attached position and a retracted position, and which is configured to supply the toner to the storage portion in a state in which the toner cartridge is at the attached position, and a moving device configured to move the toner cartridge from the attached position to the retracted position. The toner cartridge is configured such that at least part of the toner cartridge projects outside the body frame in a state in which the toner cartridge is at the retracted position.

An example charging member has a conductive support, a conductive elastic body layer on the conductive support, a first surface layer on the conductive elastic body layer, and a second surface layer on the first surface layer. The first surface layer includes a binder resin and a first plurality of first particles dispersed in the binder resin of the first surface layer, the second surface layer includes the binder resin, a second plurality of first particles, and second particles, the second plurality of first particles and the second particles being dispersed in the binder resin of the second surface layer, and an average diameter d.sub.1 of the first particles is 3 ?m?d.sub.1?6 ?m and an average diameter d.sub.2 of the second particles is 20 ?m?d.sub.2?26 ?m.

A method of operating an electrophotographic printer (100) to control the optical density of a printed image is described. The method comprises providing a printing substance on a transfer member (104); emitting a pulse of heat to heat the printing substance on the transfer member to increase flowability of the printing substance on the transfer member; and transfer-ring, from the transfer member to a substrate (108), the printing substance heated by the pulse of heat so as to provide the printed image on the substrate.

In an image forming apparatus, the image bearing member has a surface and configured to rotate about an axis. The collection device is in contact with the surface, and configured to collect materials adhered to the surface. The developing roller is configured to provide a charged toner having a first polarity. The processor is configured to perform: executing a print job in a printing period; executing, in a non-printing period, a first process in which the image bearing member is rotated at least one rotation while a holding bias is applied to the collection device, the holding bias having a second polarity opposite to the first polarity; and executing, in a non-printing period after the first process, a second process in which the image bearing member is rotated while an ejection bias is applied to the collection device, the ejection bias having the first polarity.

The electrophotographic roller has a surface layer comprising an electro-conductive elastic layer on an electro-conductive substrate. The opening of a bowl-shaped resin particle is exposed on the surface of the electrophotographic roller. The number of contact portions of the convex portion with the glass plate in a square region where a length of a nip in a direction along the circumferential direction of the electrophotographic roller of a nip formed by pressing the roller on the glass plate with a specific load applied as the length of one side and is located at any position in the nip is 8 or more. The average value of the areas of the contact portions is 10 m.sup.2 to 111 m.sup.2. The variation coefficient of the areas of the contact portions and the variation coefficient D of the areas of a plurality of Voronoi regions each including a contact portion satisfy specific relationships.

A fixing device includes a nip former including a first face to form a fixing nip, a second face being disposed upstream from the first face in a rotation direction of a rotator and defining a predetermined angle relative to the first face, and a bent portion coupling the first face to the second face. An inner circumferential surface of the rotator slides over the first face. A lateral end accumulation portion and a center accumulation portion are defined by the second face and the bent portion of the nip former and the inner circumferential surface of the rotator. The lateral end accumulation portion is accumulated with a lubricant in a first amount. The center accumulation portion is disposed inboard from the lateral end accumulation portion in an axial direction of the rotator and accumulated with the lubricant in a second amount greater than the first amount.