| 摘要 |
1,124,695. Measuring reflectivity photoelectrically. UNITED COLOR CORP. Sept. 21, 1966 [Sept.27, 1965], No.42055/66. Heading G1A. The invention is a portable apparatus for measuring diffuse reflectivity which may be used to check the amount of ink applied to printed sheets. Light from a lamp 22 Fig. 2 in housing 10 having short legs 29 passes through an aperture 27 in the housing to fall at 45 degrees on to a test piece. Light reflected by the test piece normally to its surface is detected by a photo-conductor 24. The photo-conductor is connected with a potentiometer 17 Fig. 5 to form a voltage divider which controls the current through a transistor 32 and a milliameter 34 to indicate the reflectivity of the test piece. In use the apparatus may be first located over a standard surface and the potentiometer adjusted by knob 16 until the meter 34 shows zero. The meter will then show whether a test surface is darker or lighter than the standard by deflection to the right or left. |
