| 摘要 |
PURPOSE:To check a dot or a highly sophisticated image which a person is impossible to discriminate by setting a square opening whose sides are in specific length as a window to detect the optical density of an object to be inspected. CONSTITUTION:For instance, the opening in square shape the length of whose sides is 10mum is prepared. And even one piece of toner particle 211 can be detected if present. The shape of the opening can also be rectangle or it can be in a size slightly larger than a toner particle. For instance, a square the length of whose side is 20mum is acceptable as the opening for the particle 211. The smaller the size of the opening is, the easier the detection of a toner particle come, however, if it is too small, the quantity of light that passes through it comes also too smaller, and the S/N is degraded. Accordingly, the opening is made shaped in a rectangle whose short side is about equal to or slightly shorter than the diameter of a coloring unit (for instance a toner) and the long side is about equal to or ten times as long as said diameter. |
