| 摘要 |
PURPOSE:To prevent fading, discoloring, and staining of a test pattern, by positioning a test plate having 2 test patterns selectively at a light transmitting window. CONSTITUTION:A test plate 107 is fixed to the tip of an index set to a permanent magnet 106, a white pattern for standby is provided on the face A of the plate 107, an original background color pattern for checking an amt. of toner attached on the face B, and a test pattern higher in density than the face B on the face C, and the plate 7 is installed in opposition to the window of a mask plate 103 at the end of a contact glass 1. When the first switch is turned on with a microcomputer controller, the face B is positioned at the window 103, and the face C is positioned by turning on the second switch in accordance with a quantity of current flowing through a mobile coil for the index, and the face A appears at the window 105 when the 2 switches are stopped, thus preventing discoloring, fading, and staining of the test plate 107. |
