Abstract: A reversibly allochroic toner contains a binder resin and a colorant. The colorant reversibly switches between first and second color states in response to temperature changes. The colorant exhibits a hysteresis in a temperature-color state curve thereof in which the following relationships are satisfied. Tr<TL2<TL1<TH1<TH2<Tg TH2?50° C. 20° C.?Tr?30° C. where, TH1 is a temperature at which the colorant starts to change from the first color state to the second color state, TH2 is a temperature at which the colorant completely changes to the second color state, TL1 is a temperature at which the colorant starts to change from the second color state to the first color state, TL2 is a temperature at which the colorant completely changes to the first color state, and Tg is a glass transition temperature of the binder resin.

Abstract: A reversibly allochroic toner contains a binder resin and a colorant. The colorant reversibly switches between first and second color states in response to temperature changes. The colorant exhibits a hysteresis in a temperature-color state curve thereof in which the following relationships are satisfied. Tr<TL2<TL1<TH1<TH2<Tg TH2?50° C. 20° C.?Tr?30° C. where, TH1 is a temperature at which the colorant starts to change from the first color state to the second color state, TH2 is a temperature at which the colorant completely changes to the second color state, TL1 is a temperature at which the colorant starts to change from the second color state to the first color state, TL2 is a temperature at which the colorant completely changes to the first color state, and Tg is a glass transition temperature of the binder resin.

Abstract: Disclosed is a decolorizable electrophotographic toner, including: a binder resin; and a colorant which contains at least a color developable compound and a color developing agent and is covered with an outer shell so as to have a capsule structure, wherein the number ratio of particles having an equivalent circle diameter of 0.6 ?m or more and 2.5 ?m or less of the toner when measured using a flow particle image analyzer after the toner is dispersed in an aqueous medium at a ratio of 0.08% by weight and the resulting dispersion is subjected to a stirring treatment in which stirring is performed at 5000 rpm for 30 minutes using a homogenizer (T-25 digital ULTRA-TURRAX (manufactured by IKA Japan K.K., provided with a shaft generator S25N-10G)) is 30% by number or less.

Abstract: In accordance with one embodiment, a color erasing apparatus comprises a conveyance path, a color erasing section and a control section. The conveyance path conveys a sheet. The color erasing section erases the color of an image formed with color erasable recording agent serving as recording agent containing coloring agent the color of which can be erased by heating. The control section carries out a control, in a case where the image formed on the sheet is not an image formed with the color erasable recording agent, so that the sheet is not subjected to a color erasing processing by the color erasing section.

Abstract: An image forming apparatus includes a first image forming unit configured to form a first image to be transferred to a sheet with a non-decolorizable material, and a second image forming unit configured to form a second image to be transferred to the sheet with a decolorizable material. At least a part of the second image transferred to the sheet is formed on the first image transferred to the sheet.

Abstract: According to one embodiment, a method for erasing an image includes erasing an image formed using a toner containing at least a binder resin, an electron donating color developable agent, and an electron accepting color developing agent by heating for 10 seconds or less. A color difference ?E between a region where the image is erased and a paper is 5 or less.

Abstract: In accordance with one embodiment, a color erasing apparatus comprises a conveyance path, a color erasing section and a control section. The conveyance path conveys a sheet. The color erasing section erases the color of an image formed with color erasable recording agent serving as recording agent containing coloring agent the color of which can be erased by heating. The control section carries out a control, in a case where the image formed on the sheet is not an image formed with the color erasable recording agent, so that the sheet is not subjected to a color erasing processing by the color erasing section.

Abstract: An image forming apparatus includes a first image forming unit configured to form a first image to be transferred to a sheet with a non-decolorizable material, and a second image forming unit configured to form a second image to be transferred to the sheet with a decolorizable material. At least a part of the second image transferred to the sheet is formed on the first image transferred to the sheet.

Abstract: A reversibly allochroic toner contains a binder resin and a colorant. The colorant reversibly switches between first and second color states in response to temperature changes. The colorant exhibits a hysteresis in a temperature-color state curve thereof in which the following relationships are satisfied. Tr<TL2<TL1<TH1<TH2<Tg TH2?50° C. 20° C.?Tr?30° C. where, TH1 is a temperature at which the colorant starts to change from the first color state to the second color state, TH2 is a temperature at which the colorant completely changes to the second color state, TL1 is a temperature at which the colorant starts to change from the second color state to the first color state, TL2 is a temperature at which the colorant completely changes to the first color state, and Tg is a glass transition temperature of the binder resin.

Abstract: In accordance with one embodiment, a color erasing apparatus comprises a conveyance path, a color erasing section and a control section. The conveyance path conveys a sheet. The color erasing section erases the color of an image formed with color erasable recording agent serving as recording agent containing coloring agent the color of which can be erased by heating. The control section carries out a control, in a case where the image formed on the sheet is not an image formed with the color erasable recording agent, so that the sheet is not subjected to a color erasing processing by the color erasing section.

Abstract: An image forming apparatus includes a first image forming unit configured to form a first image to be transferred to a sheet with a non-decolorizable material, and a second image forming unit configured to form a second image to be transferred to the sheet with a decolorizable material. At least a part of the second image transferred to the sheet is formed on the first image transferred to the sheet.

Abstract: A reversibly allochroic toner contains a binder resin and a colorant. The colorant reversibly switches between first and second color states in response to temperature changes. The colorant exhibits a hysteresis in a temperature-color state curve thereof in which the following relationships are satisfied. Tr<TL2<TL1<TH1<TH2<Tg TH2?50° C. 20° C.?Tr?30° C. where, TH1 is a temperature at which the colorant starts to change from the first color state to the second color state, TH2 is a temperature at which the colorant completely changes to the second color state, TL1 is a temperature at which the colorant starts to change from the second color state to the first color state, TL2 is a temperature at which the colorant completely changes to the first color state, and Tg is a glass transition temperature of the binder resin.

Abstract: Disclosed here is a method for producing a decolorizable electrophotographic toner, comprising mixing a first dispersion liquid in which a colorant is dispersed in an amount such that the content of the colorant in the toner is from 5% to 35% by weight, with a second dispersion liquid in which particles containing at least a binder resin and having a volume average particle diameter of 500 nm or less are dispersed, aggregating the colorant and the particles containing at least the binder resin, thereby obtaining aggregated particles, fusing the aggregated particles at a temperature lower than a completely decolorizing temperature of the colorant to obtain the toner, and measuring the number ratio of particles having an equivalent circle diameter of 0.6 ?m or more and 2.5 ?m or less of the toner using a flow particle image analyzer after the toner is subjected to a stirring treatment.

Abstract: According to one embodiment, a method for erasing an image includes erasing an image formed using a toner containing at least a binder resin, an electron donating color developable agent, and an electron accepting color developing agent by heating for 10 seconds or less. A color difference ?E between a region where the image is erased and a paper is 5 or less.

Abstract: An image forming apparatus includes a first image forming unit configured to form a first image to be transferred to a sheet with a non-decolorizable material, and a second image forming unit configured to form a second image to be transferred to the sheet with a decolorizable material. At least a part of the second image transferred to the sheet is formed on the first image transferred to the sheet.

Abstract: A toner set is used in a printing system that is capable of recycling a print medium and includes a first image forming portion which forms a toner image on the medium with a decolorable toner which is decolored by being heated at a temperature Te (° C.) or higher, a second image forming portion which forms a toner image on the medium with a non-decolorable toner and forms an image on the medium with at least one of the toners, and a decoloring apparatus provided with a heating portion which heats the medium on which a toner image is formed by the image forming apparatus at the temperature Te (° C.) or higher. When heated by the decoloring apparatus, the decolorable toner may be decolored without causing hot offset.

Abstract: In accordance with one embodiment, a color erasing apparatus comprises a conveyance path, a color erasing section and a control section. The conveyance path conveys a sheet. The color erasing section erases the color of an image formed with color erasable recording agent serving as recording agent containing coloring agent the color of which can be erased by heating. The control section carries out a control, in a case where the image formed on the sheet is not an image formed with the color erasable recording agent, so that the sheet is not subjected to a color erasing processing by the color erasing section.

Abstract: According to one embodiment, there is provided an image forming apparatus which forms an decolorable image and an non-decolorable image by fixing a toner image including a decolorable toner and a toner image including a non-decolorable toner or a medium. The decolorable toner has a first peak of a loss tangent tan ? at a temperature TE1, and the non-decolorable toner has a first peak of a loss tangent tan ? at a temperature TU1. A difference between the temperature TE1 and the temperature TU1 is within 20° C.

Abstract: A toner set is used in a printing system that is capable of recycling a print medium and includes a first image forming portion which forms a toner image on the medium with a decolorable toner which is decolored by being heated at a temperature Te (° C.) or higher, a second image forming portion which forms a toner image on the medium with a non-decolorable toner and forms an image on the medium with at least one of the toners, and a decoloring apparatus provided with a heating portion which heats the medium on which a toner image is formed by the image forming apparatus at the temperature Te (° C.) or higher. When heated by the decoloring apparatus, the decolorable toner may be decolored without causing hot offset.

Abstract: Disclosed is a decolorizable electrophotographic toner, including: a binder resin; and a colorant which contains at least a color developable compound and a color developing agent and is covered with an outer shell so as to have a capsule structure, wherein the number ratio of particles having an equivalent circle diameter of 0.6 ?m or more and 2.5 ?m or less of the toner when measured using a flow particle image analyzer after the toner is dispersed in an aqueous medium at a ratio of 0.08% by weight and the resulting dispersion is subjected to a stirring treatment in which stirring is performed at 5000 rpm for 30 minutes using a homogenizer (T-25 digital ULTRA-TURRAX (manufactured by IKA Japan K.K., provided with a shaft generator S25N-10G)) is 30% by number or less.