Abstract: According to one embodiment, the image forming apparatus includes an image carrier the surface of which is charged at a predetermined potential, an exposure device which forms a latent image by exposing the surface of the image carrier, a developing unit which develops a toner image generated using color erasable toner on the latent image formed on the surface of the image carrier, a transfer unit which transfers the toner image to a recording medium, and a controller which controls an operation for transferring a toner image of the color erasable toner to a printed surface of the recording medium to cover a printed portion of the recording medium to which the color erasable toner has been fixed.

Abstract: According to one embodiment, an aqueous inkjet ink includes a dispersion medium that contains water and a water-soluble polyhydric alcohol having a weight average molecular weight of 400 or more, and a pigment. The pigment accounts for less than 5 mass % of the total amount of the aqueous inkjet ink. The aqueous inkjet ink has viscosities (mPa·s) measured using a cone-plate type viscometer at 20 rpm and satisfying the following relationships: VA/VB?1.5 VA?10 mPa·s 3 mPa·s?VB?15 mPa·s, where VA is the viscosity at 30° C., and VB the viscosity at 45° C.

Abstract: According to one embodiment, the image forming apparatus includes an image carrier the surface of which is charged at a predetermined potential, an exposure device which forms a latent image by exposing the surface of the image carrier, a developing unit which develops a toner image generated using color erasable toner on the latent image formed on the surface of the image carrier, a transfer unit which transfers the toner image to a recording medium, and a controller which controls an operation for transferring a toner image of the color erasable toner to a printed surface of the recording medium to cover a printed portion of the recording medium to which the color erasable toner has been fixed.

Abstract: According to one embodiment, an aqueous inkjet ink includes a color material, water in an amount of from 50-70% by mass of the total amount of the ink, and a water-soluble organic solvent in an amount of from 29-49% by mass of the total amount. The water-soluble organic solvent contains a compound represented by the following general formula 1, and the compound represented by the following general formula 1 accounts for 10-35% by mass of the total amount of the ink. The sum of the amounts of the color material, the water, and the water-soluble organic solvent is 100% by mass or less of the ink. Where, R1 and R2 each independently represent an alkyl group having 1 to 4 carbon atoms, and m and n each represent an integer satisfying the relation: 2?m+n?6.

Abstract: According to one embodiment, an aqueous inkjet ink includes a color material, water in an amount of 50-70% by mass of the total amount of the ink, and a water-soluble organic solvent in an amount of 29-49% by mass of the total amount. The soluble organic solvent contains a compound represented by the following general formula 1 which accounts for 10-36% by mass of the total amount of ink. When the amount of the compound is equal to the amount of the solvent, the total amount of the solvent is the compound. The sum of the amounts of the color material, the water, and the water-soluble organic solvent is 100% by mass or less of the ink. Where, X1, X2, and X3 each independently represent EOn, and X4 represents an CH3CH2— or an (EOn)O—. EOn is represented by the following general formula 2, where n representing an integer of 1-5.

Abstract: According to one embodiment, an aqueous inkjet ink includes a color material in an amount of 2 to 20% by mass of the total amount of ink, water in an amount of 41 to 70% by mass of the total amount, and a water-soluble organic solvent in an amount of 20 to 53% by mass of the total amount. The solvent contains a compound represented by the following general formula 1 which accounts for 20 to 50% by mass of the total amount of ink. When the amount of compound is equal to the amount of solvent, the total amount of solvent is the compound, and the sum of the amounts of the color material, the water, and the solvent is 100% by mass or less of the ink. Where, each of a, b, and c represents an integer of 1 or more, and satisfies 3?a+b+c?15.

Abstract: According to one embodiment, an aqueous inkjet ink includes a pigment in an amount of 2 to 20% by mass of the total amount of the aqueous inkjet ink, and a dispersion medium in which the pigment is dispersed. The dispersion medium contains water in the amount of 53 to 94% by mass, with the remainder of the dispersion medium being a compound represented by the following general formula 1. The water accounts for 50 to 80% by mass of the total amount of the aqueous inkjet ink. In the general formula 1, a, b, and c may be the same or different, each representing an integer of 1 or more, and satisfy the following inequation: 4?a+b+c?10.

Abstract: This invention provides an inkjet recording apparatus which is provided with a supply unit which supplies a treatment liquid to a recording medium fed from a container and a recording unit which supplies ink to the recording medium with the treatment liquid supplied thereto and forms an image. In the inkjet recording apparatus, the treatment liquid with a first amount per unit area is supplied from the supply unit to a first region of the recording medium, and the treatment liquid with a second amount different from the first amount per unit area is supplied from the supply unit to a second region of the recording medium. The ink with the same amount per unit area is supplied from the recording unit to the first and second regions with the treatment liquid supplied thereto.

Abstract: According to one embodiment, an aqueous inkjet ink includes a color material, water as a first liquid, propylene glycol as a second liquid, and a compound represented by the following general formula (PEG) or a compound represented by the following general formula (PGC) as a third liquid. The aqueous inkjet ink has a water activity of 0.85 or less. Ra—O—(CH2CH2O)n—H ??(PEG) In the formula, Ra represents H or CH3, and n represents 3 to 14. In the formula, Rb represents a group selected from CH2CH2O and CH2CHCH3O, and j, k, p, and q may be the same or different, and represent an integer of 1 or more, and satisfy the formula: 4?j+k+p+q?8.

Abstract: According to one embodiment, an aqueous inkjet ink includes water in an amount of from 15 to 50% by mass of the total amount of the ink, a glycol mixture in an amount of from 34 to 80% by mass of the total amount of the ink, and a pigment in an amount of from 2 to 20% by mass of the total amount of the ink. The glycol mixture contains 40 to 70% by mass of propylene glycol, with the remainder being isoprene glycol.

Abstract: According to one embodiment, an aqueous inkjet ink includes a dispersion medium that contains water and a water-soluble polyhydric alcohol having a weight average molecular weight of 400 or more, and a pigment. The pigment accounts for less than 5 mass % of the total amount of the aqueous inkjet ink. The aqueous inkjet ink has viscosities (mPa·s) measured using a cone-plate type viscometer at 20 rpm and satisfying the following relationships: VA/VB?1.5 VA?10 mPa·s 3 mPa·s?VB?15 mPa·s, where VA is the viscosity at 30° C., and VB the viscosity at 45° C.

Abstract: According to one embodiment, an aqueous inkjet ink includes water and a pigment. The pigment is contained in the aqueous inkjet ink in an amount of less than 5 wt %. The queous inkjet ink has viscosities (mPa·s) measured at 25° C. using a cone-plate type viscometer and satisfying the following relationships: VB/VA?1.5 3 mPa·s?VA?15 mPa·s wherein VA represents a viscosity measured at a rotation speed of 50 rpm and VB represents a viscosity measured at a rotation speed of 2.5 rpm.

Abstract: According to one embodiment, an aqueous pigment ink includes water, a pigment, and a water-soluble polymeric compound. The pigment is contained in the aqueous pigment ink in an amount of less than 5 wt %. The aqueous pigment ink has viscosities (mPa·s) measured at 25° C. using a cone-plate type viscometer and satisfying the following relationships: 0?(VB?VA)/VB<0.05 VC/VA?1.5 3 mPa·s?VA?15 mPa·s wherein VA represents a viscosity measured at a rotation speed of 50 rpm, VB represents a viscosity measured at a rotation speed of 2.5 rpm, and VC represents a viscosity measured at a rotation speed of 50 rpm after adding calcium chloride in an amount of 0.5 wt % of the aqueous pigment ink.

Abstract: A developing unit that includes a stirring roller stirring a developer and a developing roller and develops an electrostatic latent image formed on an image carrier to form a toner image; a drive source that rotationally drives the developing roller and the stirring roller; and a control unit that switches a rotational speed of the developing roller in modes of an image formation mode and an adjustment mode, and rotationally controls the stirring roller at a first speed in the modes are provided.

Abstract: According to one embodiment, a charging device includes a charging roller and gap maintaining members. The charging roller includes a conductive roller to which charging voltage is applied and a coating layer as a member for covering the outer circumferential surface of the conductive roller, ends of the coating layer being further extended by predetermined length along an extending direction of the conductive roller than end faces of the conductive roller. The charging roller charges, in a non-contact manner, a photoconductive drum arranged near the charging roller with the charging voltage applied via the conductive roller. The gap maintaining members are respectively fixed at both ends of the charging roller in positions spaced apart from the ends of the charging roller.

Abstract: A developing unit that includes a stirring roller stirring a developer and a developing roller and develops an electrostatic latent image formed on an image carrier to form a toner image; a drive source that rotationally drives the developing roller and the stirring roller; and a control unit that switches a rotational speed of the developing roller in modes of an image formation mode and an adjustment mode, and rotationally controls the stirring roller at a first speed in the modes are provided.