An image forming apparatus includes a first photosensitive drum, a first developing unit including a first developing roller configured to contact the first photosensitive drum, a second photosensitive drum, and a second developing unit including a second developing roller configured to contact the second photosensitive drum. The image forming apparatus includes a first movement mechanism configured to move the first developing unit so that the first developing unit is located at a first contact position and a first separation position, and a second movement mechanism configured to move the second developing unit so that the second developing unit is located at a second contact position, a second separation position, and an intermediate position between the second contact position and the second separation position.

An image forming apparatus includes: a first developing roller movable between a first contact position and a first separated position; a second developing roller movable between a second contact position and a second separated position; and a controller. When a sheet interval is shorter than a first interval and is longer than or equal to a second interval, the controller maintains the first developing roller at the first contact position even after the completion of its development for a preceding sheet, controls the first developing roller to start development for a subsequent sheet, moves the second developing roller to the second separated position after the completion of its development for the preceding sheet, moves the second developing roller again to the second contact position, and controls the second developing roller to start development for the subsequent sheet after the second developing roller is moved again to the second contact position.

An image forming apparatus, having first, second, and third photosensitive drums, a first developing cartridge including a first developing roller, a second developing cartridge including a second developing roller, a third developing cartridge including a third developing roller, an exposure device, a conveyer, and a moving mechanism, is provided. The first developing roller, the second developing roller, and the third developing roller are arranged in the recited order from upstream to downstream in a moving direction for the sheet to be conveyed. When the second developing roller is at the separated position thereof, the second developing cartridge coincides with a light path of the laser beam for scanning the first photosensitive drum. When the third developing roller is at the separated position thereof, the third developing cartridge coincides with a light path of the laser beam for scanning the second photosensitive drum.

A toner container used in an image forming apparatus including an exposure unit with a light emitting diode light source includes a container body, and a cyan toner stored in the container body. A lightness L*, a hue a*, and a hue b* of the cyan toner in a powder state satisfy
26.94L*34.84,
5.13a*3.83, and
47.47b*36.78.

A toner including toner base particles each including a binder resin and a colorant, and external additive, wherein the toner satisfies conditions (a), (b), and (c) below: (a) storage elastic modulus G(50) of the toner at 50 C. and storage elastic modulus G(90) of the toner at 90 C. satisfy Formula (1);
G(50)/G(90)6.010.sup.2Formula (1) (b) a BET specific surface area Bt(m.sup.2/g) of the toner and a coverage Ct (%) of the toner base particles covered with the external additive satisfy Formula (2); and
Bt0.03Ct1.60Formula (2) (c) the external additive includes at least cohered particles,
the cohered particles are non-spherical secondary particles each formed through cohesion of primary particles, and
a number average secondary particle diameter of the cohered particles is 130 nm or greater.

A toner set includes a plurality of toners, wherein the toner set includes a first toner containing a yellow colorant and a second toner containing a cyan colorant, the first toner and the second toner each contain a binder resin containing a vinyl-based resin and a crystalline resin, and a release agent containing a hydrocarbon wax, a content of the vinyl-based resin with respect to a total mass of the binder resin is 50% by mass or more, the first toner contains the crystalline resin having a moiety having a crystal structure and a crystal nucleating agent moiety having a crystal nucleating agent, and the second toner contains the cyan colorant that is a compound represented by general formula (1). ##STR00001##

An image forming apparatus is provided that includes: first and second electrostatic latent image bearers; first and second electrostatic latent image forming devices; first and second developing devices configured to develop first and second electrostatic latent images with a colored toner and a special-color toner to form a colored toner image and a special-color toner image, respectively; a primary transfer device configured to transfer the colored toner image and the special-color toner image onto an intermediate image bearer in an overlapping manner to form a composite toner image; a secondary transfer device configured to transfer the composite toner image onto a recording medium; and a fixing device configured to fix the composite toner image thereon. The special-color toner comprises plate-like and/or film-like pigments. An absolute difference in volume resistivity between the special-color toner and the colored toner is 0.30 log cm or less.

In an image forming apparatus, a first photosensitive drum is disposed upstream of a second photosensitive drum in a conveyance direction. Each of first and second developing rollers is movable between a contact position contacting a corresponding photosensitive drum and a separated position separated from the corresponding photosensitive drum. In a first case where a color print process is executed, a first moving mechanism starts moving the first developing roller toward the contact position, a manual feed roller starts picking up the sheet on a manual feed tray, and a second moving mechanism starts moving the second developing roller toward the contact position. In a second case where the monochrome print process is executed, the manual feed roller starts picking up the sheet on the manual feed tray, and the second moving mechanism starts moving the second developing roller toward the contact position.

An image forming apparatus includes: a first gear train including a first clutch; a second gear train including a second clutch; a third gear train including a third clutch; a fourth gear train including a fourth clutch; a motor including an output shaft; an output gear rotatable with the output shaft; a fifth gear train connected to the first and second clutches; and a sixth gear train connected to the third and fourth clutches. The first clutch engages transmission of a driving force to a first developing unit, the second clutch engages transmission of a driving force to a second developing unit, the third clutch engages transmission of a driving force to a third developing unit, and the fourth clutch engages transmission of a driving force to a fourth developing unit. The fifth and sixth gear trains are connected to the output gear independently from each other.

A toner container used in an image forming apparatus including an exposure unit with a light emitting diode light source. The toner container including a container body, and a cyan toner stored in the container body. The cyan toner includes a binder resin, at least one pigment, a charge control agent, and an external additive. The at least one pigment includes at least Pigment Blue. A lightness L*, a hue a*, and a hue b* of the cyan toner in a powder state satisfy: 30.04L*33.68, 1.75a*0.71, and 47.47b*45.08.