| abstract |
(57) [Summary] The main object is to provide a material capable of detecting ozone more easily. The image forming apparatus has at least one color-change layer made of an ozone-detecting ink that changes color with ozone on a substrate, and at least one non-color-change layer made of an ink that does not change color with ozone. An ozone indicator, wherein a color-changing layer and a non-color-changing layer are formed such that a part or all of the color-changing layer is exposed to an ozone atmosphere. |