A developing device includes a development casing, a developer carrying member, and a regulating blade. The development casing has an opening part. The developer carrying member has a developing area. The development casing has a blade facing part. The regulating blade includes a fixed part and a regulating part, and a space between the regulating part and the blade facing part is larger than a space between the fixed part and the blade facing part. The developing device further includes a blade seal member. The blade seal member is disposed between the regulating blade and the blade facing part, and is glued to an upstream side surface of the regulating part in the rotation direction, so as to seal a gap between the regulating blade and the blade facing part.

The developing device includes a development container, a developer carrier, and a restricting blade. The development container has an opening. The developer carrier has a development area. The development container includes a pair of side frames, and a pair of side wall portions. In each of the pair of side wall portions, a seal member insertion hole extending through in the rotation-axial direction is formed at a position facing an end edge of the restricting blade in the rotation-axial direction. The developing device includes a blade-side side seal inserted in the seal member insertion hole to block a gap between the restricting blade and the side wall portion.

There are provided a developer accommodating portion for accommodating the developer, a discharge portion formed with a discharge opening for discharging the developer accommodated in the developer accommodating portion, and an engaging portion 30. The engaging portion 30 is engaged with an engaged portion 11b with a mounting operation of a developer supply container 1 to displace a developer receiving portion 11 in an upward direction U so that the receiving opening communicates with the discharge opening. The engaging portion 30 has a holding portion 31 which is provided rotatably about a rotation shaft 41 and is provided with holding portion 21 to be engaged with the engaged portion 11b to hold the engaged portion 11b. With the mounting operation, the engaging portion 30 rotates about the rotation shaft 41 so that the engaged portion 11b held by the holding portion 31 moves upward U.

A developing device capable of stably collecting untransferred toner collected from the photoconductor drum to the developing roller to the feed roller and suppressing occurrence of development ghosts, and an image forming apparatus including the same are provided. A developing device has a developing roller facing a photoconductor drum, a feed roller, and a restriction blade. The feed roller forms a feed nip part with the developing roller by contacting with the circumferential surface of the developing roller, and collects toner from the developing roller while feeding the toner to the developing roller. The Asker-C hardness of the developing roller is in the range of 50 to 80, both inclusive, the width of the feed nip part is in the range of 0.2 to 1.5 mm, both inclusive, and a compressive load to be applied to the feed roller is in the range of 0.2 to 1.5N, both inclusive.

An image forming apparatus includes a controller, a drive unit, a developer bearing member, a regulation blade, and a sheet member. During non-image forming, the controller executes a control mode for controlling the drive unit to rotatably drive the developer bearing member in a second direction opposite to a first direction, and then rotatably drive the developer bearing member in the first direction. A portion above a horizontal line passing through a tip of the regulation blade out of the sheet member is disposed in a moving path of a developer born by the developer bearing member when the drive unit rotatably drives the developer bearing member in the second direction in the control mode, and is not disposed in the moving path of the developer born by the developer bearing member when the drive unit rotatably drives the developer bearing member in the first direction during image forming.

An image forming apparatus includes a photosensitive member, a charging member, a developing member, a first contacting member contacting to the developing member, and first to third power sources. The first power source generates a first voltage lower and supply to the charging member. The second power source generates a second voltage lower than the first voltage from the first voltage and applies to the first contacting member. The third power source generates a third voltage lower than the second voltage from the second voltage and applies to the developing member.

A developing apparatus for developing a latent image formed on an image bearing member includes a developer carrying member configured to carry a developer including toner and magnetic carrier and including a developer carrying surface having a plurality of grooves, a magnet, provided inside the developer carrying member, configured to attract the developer on the developing carrying surface, and a regulating member, provided spaced from the developer carrying member and configured to regulate an amount of the developer carried on the developer carrying surface.

A magnet roller employs a magnetic pole pattern in which a first magnetic pole arranged substantially opposing a regulating blade in an upstream side of a rotation direction of a developing sleeve and a second magnetic pole next to the first magnetic pole in the upstream side have the same polarity, an opposing member having surface roughness higher than at least a particle diameter of carrier is arranged opposing the magnet roller at a position where magnetic force between the first magnetic pole and the second magnetic pole next to the first magnetic pole in the upstream side is almost zero, and an apex of a partition wall provided between a developer bearing member and a developer conveying member provided in a first chamber is positioned below a region where magnetic force formed by the magnet roller is almost zero.

A process cartridge includes an electrophotographic photosensitive drum, a developer bearing roller, and a developer regulating member, the developer regulating member and the developer bearing roller constituting a contact region, the contact region having a width larger than the width of the developing region in the direction of the axis of the developer bearing roller and extending in the circumferential direction of the developer bearing roller, the developer regulating member having a protruding portion that protrudes over the entire width of the contact region from the end portion on the upstream side of the contact region toward the upstream side in the rotational direction of the roller, and the length of the protruding portion in a region corresponding to the developing region being substantially constant and larger than the length of the protruding portion at the location corresponding to the end portion in the width direction of the contact region.

At an end, in a longitudinal direction, of an opening in a container containing a magnetic developer, an overlap portion is provided in which a developer bearing member, a regulating member, a sealing member, and the container are arranged so as to sequentially contact one another in a direction orthogonal to a rotation axis direction. A magnetic field generating member provided inside the developer bearing member has a first area where a value of a magnetic flux density is a predetermined value in the rotation axis direction and a second area including a local minimum portion in which the value is a minimum value, within a range from an end of the second area connected to the first area to an outer end of the overlap portion in the rotation axis direction.