An image forming apparatus includes a formation unit configured to form an image by using a plurality of cartridges that are detachable from the image forming apparatus, each cartridge having a storage unit and a member for forming the image; and a control unit configured to set an image forming condition for image formation. The control unit reads identification information from each storage unit of at least two cartridges out of the plurality of cartridges, the identification information indicating a version of a corresponding cartridge, and the control unit sets the image forming condition based on a combination of versions of the at least two cartridges.

Yellow toner with excellent cleanability, transferability and device contamination resistance is provided. When intensity of spectrum at wavenumber ?, at which total intensity of Raman spectrums of toner particles from 950 cm.sup.?1 through 3,250 cm.sup.?1 in Raman spectroscopy of toner is maximum, is normalized to 1, and distribution is generated for ?300 particles regarding LC calculated by [LC (%)=CH.sub.5 rate (%)?CH.sub.c rate (%)] based on CH.sub.c rate (%) defined as [(I.sub.nc?I.sub.ave)/I.sub.ave]?100 and CH.sub.s rate (%) defined as [(I.sub.ns?I.sub.ave)/I.sub.ave]?100 where I.sub.n and I.sub.ns represent integrated intensities of spectrums of center and surface portions of each particle from 2,750 cm.sup.?1 through 3,250 cm.sup.?1, and I.sub.ave represents average of I.sub.nc and I.sub.ns of all particles, percentage by number of particles having LC deviating from LC distribution median by absolute value of ?25.0; is ?1.0% by number and ?25.0% by number.

A developing unit includes a body and a displacement member. The displacement member is to be held by the body in a first mode in a first mounting state, and is to be held by the body displaceably between the first mode and a second mode in a reversible fashion in a second mounting state. The first mounting state is a state in which a first toner cartridge is mounted on the developing unit. The second mounting state is a state in which a second toner cartridge is mounted on the developing unit.

A developer including developer particles. Each developer particle includes a binder resin, a brilliant pigment whose principal component is aluminum, a yellow pigment, a magenta pigment, a reddish-orange fluorescent dye, and a yellow fluorescent dye. When an average particle diameter of the brilliant pigments included in the developer particles is expressed as D (m), a number proportion of the developer particles having particle diameters in a range from 4 m to 1.2D m in the whole developer particles is less than or equal to 4%.

An image forming apparatus includes a main assembly, a cartridge, a rotationally movable member, an engaging portion, and a flexible member integrally including a first supported portion, a second supported portion, and a regulating portion. A position of the regulating portion of the flexible member relative to the engaging portion is changeable by a change in a flexed state of a portion of the flexible member between the first supported portion and the second supported portion, in interrelation with a change in relative position between the first supported portion and the second supported portion with rotational movement of the rotationally movable member When the rotationally movable member is in the first position, the regulating portion is in a regulating position to limit the elastic deformation of the engaging portion.

Provided is an image forming apparatus wherein a transfer material transport guide 35 is disposed in an optical sensor unit 29 to support a color deviation sensor, which is disposed near an intermediate transfer belt 6. By changing the position of the optical sensor unit 29, the grounding path of the transfer material transport guide 35 can be changed, and both the transfer bias leak prevention for the transfer material transport guide 35 and the electrostatic breakdown prevention for the color deviation sensor can be implemented. As a result, the apparatus can be downsized, and only when the intermediate transfer belt is replaced, the optical sensor unit 29 can be moved to create a space necessary for the replacement.

An image forming apparatus, having process units, a transfer unit, a motor, first through fourth cams, a color-linkage gear train, a monochrome-transmission gear train, and a color-transmission gear train, is provided. Each of the process units has a developing unit including a developing roller and a drum unit including a photosensitive drum. The color-linkage gear train rotates the first cam, the second cam, and the third cam in shifted phases. The monochrome-transmission gear train transmits a driving force from the motor to a monochrome clutch, which engages and disengages transmission of the driving force from the monochrome-transmission gear train to the fourth cam. The color-transmission gear train transmits the driving force from the motor to a color clutch, which engages and disengages transmission of the driving force from the color-transmission gear train to the color-linkage gear train.

An image forming apparatus includes: a formation unit configured to form an image by using a plurality of cartridges that are detachable from the image forming apparatus, each cartridge having a storage unit and a member for forming the image; and a control unit configured to set an image forming condition for image formation. The control unit reads identification information from each storage unit of at least two cartridges out of the plurality of cartridges, the identification information indicating a version of a corresponding cartridge, and the control unit sets the image forming condition based on a combination of versions of the at least two cartridges.

The present invention relates to an image forming method in which an electrophotographic cartridge is disposed in at least four-color tandem with respect to a transfer material transporting body, in which, in a case where a fixing step side of the transfer material transporting body is set as a downstream side, and a cleaning step side of the transfer material transporting body is set as an upstream side, a total amount of use amount of specific external additives contained in the toner for each of the color electrophotographic cartridges is adjusted to a specific amount, and a specific amount of a specific external additive is used for toner provided in the electrophotographic cartridge on the most downstream side.

A developer including developer particles. Each developer particle includes a binder resin, a brilliant pigment whose principal component is aluminum, a yellow pigment, a magenta pigment, a reddish-orange fluorescent dye, and a yellow fluorescent dye. When an average particle diameter of the brilliant pigments included in the developer particles is expressed as D (m), a number proportion of the developer particles having particle diameters in a range from 4 m to 1.2D m in the whole developer particles is less than or equal to 4%.