A developing device includes a rotatable developing sleeve for carrying a developer including toner and a magnetic carrier and for developing an electrostatic latent image, formed on an image bearing member, in a developing region where the developer contacts the image bearing member; and a magnetic field generating portion provided inside the developing sleeve and having a developing pole provided at a position opposing the image bearing member in order to form the developing region, wherein a ratio of an 80%-value-width of magnetic flux density of the developing pole with respect to a normal direction of the developing sleeve to a half peak width of the magnetic flux density of the developing magnetic pole with respect to the normal direction is 0.65 or more, and with respect to a rotational direction of the developing sleeve, a magnetic force of the developing pole in the normal direction of the developing sleeve in each of neighborhoods of both end portions of the developing region is larger than a magnetic force of the developing pole at a central portion of the developing region.

A semiconductive roller is provided which includes a roller body including a tubular inner layer of an inner layer elastic material containing a softener, and an outer layer of an outer layer elastic material provided on an outer periphery of the inner layer. The outer layer elastic material has a swelling percentage of not higher than 1% as measured when the outer layer elastic material is immersed in the softener at 100 C. for 24 hours. Thus, the semiconductive roller has proper flexibility to be substantially free from imaging failures such as white voids, image density reduction and fogging, and is less liable to cause the contamination of a photoreceptor body and the like and the associated defective image formation which may otherwise occur due to the bleeding of the softener.

An image forming apparatus, a process cartridge, and a developing unit includes a developer carrying member to carry developer, first and second rotary members arranged in parallel to each other and configured to rotate to agitate and convey the developer, and an enclosure having an inside space to contain the developer, the inside space being divided by a partition with communication openings formed therein at opposite ends thereof into a first chamber configured to maintain the developer above a first level and to hold the first rotary member therein which supplies the developer to the developer carrying member while agitating and conveying the developer, and a second chamber configured to communicate with the first chamber through the communication openings, to maintain the developer at a second level lower than the first level, and to hold the second rotary member therein which circulates the developer with the first chamber through the communication openings.

An ink let recording medium of this disclosure has a substrate and at least one or more ink receiving layers on the substrate, in which a first ink receiving layer which is the outermost surface layer contains anionic inorganic particles having an average particle diameter of 3.0 m or more, a binder, a cationic polymer, and a polyvalent metal salt, the content of the polyvalent metal salt based on the anionic inorganic particles in the first ink receiving layer is 5 mass % or more and 40 mass % or less, the content ratio of the polyvalent metal salt to the cationic polymer in the first ink receiving layer (Content of polyvalent metal salt/Content of cationic polymer) is 1.0 or more and 8.0 or less, and the arithmetic average roughness Ra of the surface of the recording medium is 1.0 m or more.

A developer cartridge is described. The developer cartridge detachably mountable on a tandem type photosensitive unit slidable to a drawn-out position and a mounted position with respect to an image forming apparatus body may include a casing; a developer carrier rotatably supported on one end portion of the casing for carrying a developer; a pair of upright portions arranged on another end portion of the casing at an interval from each other in the axial direction of the developer carrier to extend from another end portion of the casing in a detaching direction for the developer cartridge; and an elastically deformable coupling portion extending in the axial direction of the developer carrier for coupling the upright portions with each other.

A semiconductive roller is provided which includes a roller body including a tubular inner layer of an inner layer elastic material containing a softener, and an outer layer of an outer layer elastic material provided on an outer periphery of the inner layer. The outer layer elastic material has a swelling percentage of not higher than 1% as measured when the outer layer elastic material is immersed in the softener at 100 C. for 24 hours. Thus, the semiconductive roller has proper flexibility to be substantially free from imaging failures such as white voids, image density reduction and fogging, and is less liable to cause the contamination of a photoreceptor body and the like and the associated defective image formation which may otherwise occur due to the bleeding of the softener.

The present disclosure provides a developing cartridge. The developing cartridge includes a developing roller; a developing frame, where the developing frame includes a cartridge body, a driving-end cover and a conductive-end cover, the driving-end cover is at an end of the cartridge body along a length direction of the cartridge body, and the conductive-end cover is at another end of the cartridge body along the length direction of the cartridge body; a separation contact part; a tension spring; a force-receiving part, where the force-receiving part is configured to receive and transmit a driving force to rotate the developing roller; and an electrode assembly, where the electrode assembly is at an inner side of the conductive-end cover and electrically connected to an end of the developing roller; and an opening is formed on the conductive-end cover, and a portion of the electrode assembly is exposed through the opening.

A developing device includes a developing roller, a toner supply roller, a regulating blade, a casing, a toner-reception supporting member, a toner reception member, and a vibration generating unit. The toner-reception supporting member is opposed to the developing roller or the toner supply roller between the regulating blade and the image carrier. The toner reception member is located so as to make a downward slope toward the toner supply roller side from the image carrier side along a longitudinal direction of the toner-reception supporting member. The toner reception member has a toner receiving surface that receives the toner dropping from the developing roller. The vibration generating unit vibrates the toner reception member. The toner reception member includes a sheet-shaped toner crushing member attached to overlap approximately a whole region of the toner receiving surface in a longitudinal direction. The toner crushing member is swingably supported with respect to the toner receiving surface.

An ink let recording medium of this disclosure has a substrate and at least one or more ink receiving layers on the substrate, in which a first ink receiving layer which is the outermost surface layer contains anionic inorganic particles having an average particle diameter of 3.0 m or more, a binder, a cationic polymer, and a polyvalent metal salt, the content of the polyvalent metal salt based on the anionic inorganic particles in the first ink receiving layer is 5 mass % or more and 40 mass % or less, the content ratio of the polyvalent metal salt to the cationic polymer in the first ink receiving layer (Content of polyvalent metal salt/Content of cationic polymer) is 1.0 or more and 8.0 or less, and the arithmetic average roughness Ra of the surface of the recording medium is 1.0 m or more.

A developer cartridge is described. The developer cartridge detachably mountable on a tandem type photosensitive unit slidable to a drawn-out position and a mounted position with respect to an image forming apparatus body may include a casing; a developer carrier rotatably supported on one end portion of the casing for carrying a developer; a pair of upright portions arranged on another end portion of the casing at an interval from each other in the axial direction of the developer carrier to extend from another end portion of the casing in a detaching direction for the developer cartridge; and an elastically deformable coupling portion extending in the axial direction of the developer carrier for coupling the upright portions with each other.