Provided is an electrophotographic developer set having a toner and a powder adhesive, wherein the toner comprises a thermoplastic resin A; the powder adhesive comprises a thermoplastic resin B and a wax A; the wax A has two or more ester groups in the molecule; the thermoplastic resin B has an ester group; and in a viscoelasticity measurement, with Gt′(100) (Pa) being a storage elastic modulus at 100° C. of the toner, and Gb′(100) (Pa) being a storage elastic modulus at 100° C. of the powder adhesive, Gb′(100) is 1.00×10.sup.5 Pa or less, and Gt′(100)/Gb′(100) is 1.20 or more, as well as a method for producing a bonded product using the above electrophotographic developer set.

A white toner includes a toner particle that contains a binder resin containing a hybrid resin in which an amorphous resin unit and a crystalline polyester resin unit are chemically bonded to each other, surface-treated titanium oxide, and a release agent, in which a proportion of Al atoms in a surface of the surface-treated titanium oxide is 3 atomic % or greater and 20 atomic % or less, and a proportion of Ti atoms in the surface is 5 atomic % or greater and 15 atomic % or less.

An image forming apparatus includes plural image forming units and a controller. The plural image forming units are configured to form images of colors using colorants, respectively. The controller is configured to perform control such that the plural images formed by the plural image forming units are output as one image onto a recording medium. At least two of the image forming units are configured to form images using colorants of special colors, respectively and are arranged in succession.

An image forming apparatus, includes: plural image forming units each including an image holding member and configured to form an image that is to be transferred to a recording medium on the image holding member using a dry toner, the number of the plural image forming units being at least five; and plural developing devices each of which is provided in each of the plural image forming units and supplied with the dry toner and a dry carrier, each of the plural developing devices including a dry toner adhering unit that has a length equal to or longer than a length of a long side of an A3 size and to which the dry toner adheres, the dry toner adhering unit being configured to cause the dry toner adhering to the dry toner adhering unit to adhere to the image holding member.

A toner includes a binder resin including a copolymer resin containing structural units derived from crystalline and non-crystalline resins, respectively. Spin-spin relaxation time (t50) of the toner at 50° C. measured by pulse NMR is ≦0.05 msec., spin-spin relaxation time (t130) at 130° C. when warmed from 50° C. to 130° C. is >15 msec., and spin-spin relaxation time (t′70) at 70° C. when cooled from 130° C. to 70° C. is ≦1.00 msec. A binarized image obtained by binarizing a phase image of the toner observed by a tapping mode AFM based on intermediate value between maximum and minimum phase difference values in the phase image includes first phase difference images constituted by large phase-difference portions and a second phase difference image constituted by a small phase-difference portion. The first phase difference images are dispersed in the second phase difference image. The dispersion diameter of the first phase difference images is 150 nm or less.

An image forming apparatus includes lock mechanisms, a second detection processing portion, and a second release processing portion. The lock mechanisms regulate attachment and detachment of the developer storage portions attached to the attachment portions. The second detection processing portion detects whether or not any of the image forming units has an abnormality. The second release processing portion can release a regulation on attachment and detachment of two or more developer storage portions corresponding to two or more image forming units that include at least an image forming unit adjacent to the image forming unit detected to have the abnormality.

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: 30.04≤L*≤33.68, −1.75≤a*≤0.71, and −47.47≤b*≤−45.08.

An electrostatic charge image developing toner set includes a brilliant toner including toner particles that include a brilliant pigment and a first binder resin, a black toner including toner particles that include a second binder resin, and a color toner except a black toner, including toner particles that include a third binder resin, wherein the brilliant toner, the black toner and the color toner satisfy Expression (1): Dielectric loss factor of the brilliant Toner>Dielectric loss factor of the black toner>Dielectric loss factor of the color toner and Expression (2): 25×10.sup.−3≦(Dielectric loss factor of the brilliant toner)−(Dielectric loss factor of the color toner)≦95×10.sup.−3.

A toner includes a base particle including a polyester resin and a colorant. A sea-island structure is observed by a transmission electron microscope (TEM) in a cross-sectional image of the toner. The island structure includes the colorant and has an average diameter of from 0.2 μm to 1.0 μm, and the number of the island structure is from 5 to 30.

An image forming apparatus for developing an electrostatic latent image with developer includes a development part, a transfer part, and a fuser. The developer includes first developer with a first coloring agent of yellow and a first external additive, and second developer with a second coloring agent of a color other than yellow and a second external additive. A first peeling rate of the first external additive by a following formula (1) is smaller than a second peeling rate of the second external additive by a following formula (2),

the first peeling rate (%)=[1−(X1/Y1)]×100  (1)

the second peeling rate (%)=[1−(X2/Y2)]×100  (2) X1, Y1 are amounts (weight %) of the first external additive in the first developer after/before the ultrasonic waves are applied, X2, Y2 are amounts (weight %) of the second external additive in the second developer after/before the ultrasonic waves are applied.