| 摘要 |
PURPOSE:To detect the density highly accurately step by step by one measurement, by changing a black and white judging reference in correspondence with the optical brightness, which is measured with respect to a medium. CONSTITUTION:The light of a lamp 101, which is reflected by a medium 102 that detects the density of printing, is converted into an electric signal by an optical sensor 104 through a lens system 103. The signal is sent to a black and white judging reference generating part 106 and a density judging part 107 through an amplifier part 105. An output 301 of the amplifier part 105 is compared with an output 302 of the generating part 106 in the judging part 107. At this time, the output 302 is set so that it is changed with the output 301. When the density on the medium 102 is larger than the output 302, white is determined. When the density is smaller, black is determined. By the adequate setting of the output 301, the density of the printing and the like on the medium 102 can be detected highly accurately step by step. |
