A toner, including a binder resin, a release agent, and a colorant, wherein a total amount of hydrocarbon compounds having 33 to 35 carbon atoms in the toner measured by ion attachment mass spectrometry (IAMS) is 40% to 70% in terms of a signal intensity ratio.

A resin particle contains a binder resin containing a polyester resin containing polyethylene terephthalate and a diol component of propylene glycol and a release agent containing an ester wax.

An image forming apparatus includes an image forming unit having an image carrier, a charging device, and a development device, so as to perform image formation using toner, an exposure device, an image density sensor, a development voltage power supply, a control unit, and a layer thickness detection mechanism. The control unit can perform calibration, in which density of a reference image formed by the image forming unit is detected by the image density sensor, and the development voltage is adjusted based on a detection result, so as to adjust the density of the toner image. The layer thickness detection mechanism detects thickness of the photosensitive layer. Along with a decrease in the thickness of the photosensitive layer detected by the layer thickness detection mechanism, the control unit stepwisely decreases an upper limit value of the DC voltage from a reference value, when adjusting the development voltage in the calibration.

A carrier is provided. The carrier includes a magnetic core particle and a resin layer coating a surface of the magnetic core particle. The resin layer includes a resin, a conductive particle including tungsten tin oxide, and a chargeable filler.

A toner cartridge including a carrier container in which one surface needed for discharge of carriers faces a toner discharge outlet, an image forming apparatus, and a method for controlling the image forming apparatus are provided. The toner cartridge includes a case, a toner container in the case so as to contain the toners; a toner outlet disposed over the case so as to discharge the container toner to the outside; and a carrier container including carriers therein such that one surface of the carrier container, through which the included carriers are discharged, is arranged to face the toner outlet.

A carrier for electrostatic image development includes magnetic particles having internal pores, and a resin composition disposed in at least some of the internal pores and containing a resin and inorganic particles including at least one selected from the group consisting of silica, alumina, and calcium carbonate.

An electrostatic charge image developing carrier contains a core particle and a resin coat layer on a surface of the core particle, wherein the core particle has a BET specific surface area of from 0.05 m.sup.2/g to 0.10 m.sup.2/g, and the resin coat layer contains a nitrogen-containing (meth)acrylate resin.

A two-component developer includes a toner and a carrier. The toner includes a plurality of toner particles. The carrier includes a plurality of carrier particles. Each of the toner particles includes a toner core and a shell layer disposed over the surface of the toner core. The toner has a charge decay constant of at least 0.020 and no greater than 0.050 as measured with the toner particles in an external additive-free state. The carrier has a volume resistivity of at least 1.010.sup.12 .Math.cm.

An image forming system including: a two-component developer; and an image forming apparatus including at least one of a photoreceptor including a support made of an aluminum alloy or a developer bearing member including a developing sleeve made of an aluminum alloy. A static resistance value of a carrier contained in the two-component developer is in a range of 10.sup.8 .Math.cm or more and less than 10.sup.12 .Math.cm. A silicon content in the aluminum alloy forming at least the support of the photoreceptor or the developing sleeve of the developer bearing member is in a range of more than 0.6% by mass and 12.6% by mass or less.

A developing apparatus that develops an electrostatic latent image on an image supporting body using developer including toner and carrier includes a circulation path where the developer circulates, a discharge path connected to the circulation path through which some of the developer passes, and a first recycle path connected to the discharge path and allowing some of the developer flowing into the discharge path to return to the circulation path. The discharge path includes a discharge opening for discharging the developer flowing into the discharge path, and a first return opening for connecting to the first recycle path. The first return opening is located on an upper side in a vertical direction with respect to the discharge opening and located on an upstream side in a pass-through direction of the developer flowing into the discharge path.