According to one embodiment, an ink which can be decolored upon heating is provided. Colored images can be formed with the ink by various methods, such as ink jetting or the like, then later the images can be decolored with heat. An ink according to an embodiment contains a color developable compound, a color developing agent that causes the color developable compound to develop a color, a nonaqueous solvent, and a decoloring agent that is insoluble in the nonaqueous solvent and decolors the color developable compound upon heating.

In accordance with an embodiment, an image decoloring apparatus comprises a conveyance path configured to convey a sheet on which an image is formed with a coloring agent that is decolored by heat; a first heat roller configured to be arranged at the upstream side of the conveyance path; and a second heat roller configured to be arranged at the downstream side of the conveyance path. Each of the first heat roller and the second heat roller includes a cylindrical portion and a heat source. The thickness of the cylindrical portion constituting the first heat roller is larger than the thickness of the cylindrical portion constituting the second heat roller. In this way, the heat capacity of the first heat roller is also larger than the heat capacity of the second heat roller.

Provided is an image erasing method including heating a thermoreversible recording medium with laser beams to erase an image which has been recorded on the thermoreversible recording medium, the thermoreversible recording medium reversibly changing between a colored state and a decolored state depending on a heating temperature and a cooling time; and measuring at least one of a surface temperature of the thermoreversible recording medium and an erasing environmental temperature before a beginning of erasing the image to obtain a measured temperature value and controlling a heating time with the laser beams to be emitted for erasing the image depending on the measured temperature value.

A drawing system according to an embodiment of the present disclosure includes a storage, an operation section, and a drawing section. The storage stores a characteristic function that derives output setting values of light sources on the basis of drawing coordinates, an absorbance correlation value, and gradation values in a leuco color space. The operation section derives the output setting values by inputting, to the characteristic function, the drawing coordinates, gradation values of leuco image data described in the leuco color space, and an absorbance correlation value obtained by measuring the recording medium. The drawing section includes the light sources, and controls output of the light sources on the basis of the output setting values derived by the operation section to thereby perform drawing on the recording medium.

A drawing method according to an embodiment of the present disclosure includes, when performing drawing on a thermal recording medium that includes a light-transmitting member above a recording layer, obtaining information regarding the light-transmitting member, predicting an optical axis deviation of a laser beam in the recording layer from the information regarding the light-transmitting member, and calculating a correction amount from a result of the prediction of the optical axis deviation.

A reversible recording medium according to an embodiment of the present disclosure is a reversible recording medium that includes recording layers and heat-insulating layers that are alternately stacked, in which the recording layers each include a reversible heat-sensitive color developing composition and a first light-heat converting agent. In this reversible recording medium, the recording layers are different from each other in a developing color of their respective reversible heat-sensitive color developing compositions and are different from each other in an absorption wavelength of their respective first light-heat converting agents. This reversible recording medium further includes a heat-generating layer that includes a second light-heat converting agent having an absorption wavelength that is different from the absorption wavelength of the first light-heat converting agent included in each of the recording layers.

A drawing and erasing apparatus includes a light source section that includes a plurality of laser elements different from each other in emission wavelength, a multiplexer that multiplexes a plurality of types of laser light beams outputted from the plurality of laser elements, a scanner section that performs scanning with multiplexed light outputted from the multiplexer on a reversible recording medium including a plurality of recording layers, the plurality of recording layers being reversible and different from each other in developed color hue, and a controller that controls a main scanning speed and a sub-scanning speed of the scanner section to cause the scanner section to perform overlapping scanning of a predetermined region on the reversible recording medium during erasure of information written on the reversible recording medium.

A forgery prevention medium includes a substrate and a specific invisible material layer directly or indirectly laminated on the substrate, having a specific invisible material reversibly and visually recognized through a predetermined process disposed thereon in a plane shape, and having a part of the specific invisible material inactivated in accordance with a visualized image pattern.

A recording medium according to one embodiment of the present disclosure includes a recording layer and an optical thin film. The recording layer includes a heat-sensitive color-developing composition and a photothermal conversion material. The photothermal conversion material absorbs a wavelength in an infrared region and generates heat. The optical thin film is provided on one surface of the recording layer. The optical thin film reflects the wavelength in the infrared region and transmits a wavelength in a visible region.

In a drawing method according to an embodiment of the present disclosure, when performing drawing on a thermal recording medium that includes, above a recording layer, a light-transmitting member having an uneven shape in a plane, an optical compensator having one surface and another surface is provided on the light-transmitting member to cause the one surface and the light-transmitting member to face each other, and the thermal recording medium is irradiated with a laser beam via the optical compensator. The one surface of the optical compensator has a shape that fits the uneven shape of the light-transmitting member, and the other surface is flat and opposed to the one surface.