| 摘要 |
An electrostatic voltmeter (10), which can be used in the image reading device of a multi-mode copier/printer (Figs, 5, 6) comprises a microdeflector probe (13) for measuring the charge on a surface (35), e.g. the photoconductive surface in xerography. The probe comprises a flexible finger (14) cantilevered on a base (16) which is electrically biased to a predetermined potential Vre via connection (17). A sensing electrode (27) on the finger has a portion (33) which can be positioned in spaced relation adjacent surface (35), the capacitive relation thus established creating on the sensing electrode a charge representative of the charge on the surface (35). The potential difference between the finger and the base causes the finger to deflect. This deflection can be converted to a signal representing the charge on the surface (35) e.g. by directing a beam (41) of light and detecting the reflected beam with a detector (45) which can be arranged to receive the reflected light only when the finger undergoes deflection of predetermined amplitude. <IMAGE> |
