Abstract: An apparatus for detecting the fluorescence of a luminescent material. Photo-semiconductors receiving the visible fluorescence from a target luminescent material and directly from a discharge lamp are electrically coupled to oppose each other resulting in a single-channel detector inherently balanced and insensitive to variations in the excitation stimulus. The photo-semiconductor output is sent through a second harmonic amplifier making available a phase detection of the fluorescence instead of an amplitude detection. The phase of the signal is compared with a known phase from the excitation power source. By adding signals that either reinforce or oppose, the phase information is converted back to amplitude information at a voltage level that can be easily detected. The compared output then triggers an indicator producing an indication of the amount of fluorescence of the target luminescent material.

Abstract: An electrostatic latent image residing on an electrically insulating surface used to induce a similar image on a sectionally conductive member by bringing one surface of the sectionally conductive member into proximity with the latent image while the opposite surface of the sectionally conductive member is brought to ground potential. The sectionally conductive member is then removed from proximity with the latent image. To prevent electrical breakdown during removal, a grounded electrode is placed adjacent the surface of the sectionally conductive member opposite the latent image but separated from the sectionally conductive member by a thin electrically insulating layer. A latent image is thus formed on the sectionally conductive member which can be developed by conventional means such as with electroscopic materials well known in the xerographic art.

Abstract: An electrostatic latent image residing on an electrically insulating surface used to induce a similar image on a sectionally conductive member by bringing one surface of the sectionally conductive member into proximity with the latent image while the opposite surface of the sectionally conductive member is brought to ground potential. The sectionally conductive member is then removed from proximity with the latent image. To prevent electrical breakdown during removal, a grounded electrode is placed adjacent the surface of the sectionally conductive member opposite the latent image but separated from the sectionally conductive member by a thin electrically insulating layer. A latent image is thus formed on the sectionally conductive member which can be developed by conventional means such as with electroscopic materials well known in the xerographic art.

Abstract: In an electrostatographic imaging apparatus, comprising, an imaging member with a surface capable of retaining an electrostatic latent image, a donor member with a surface capable of supporting a layer of particulate image-developing material, and means for maintaining the surface of said donor member in close proximity to the surface of said imaging member, the improvement which comprises a donor member having permanently disposed on its surface a plurality of raised, granular elements for self-spacing the donor member from the imaging member.

Abstract: Electrostatic imaging apparatus for transfer development of latent images employing a developer donor member with a plurality of raised micro-pins on the donor surface, for self-spacing the donor from the imaging surface. Methods of producing such donors are disclosed.

Abstract: Feedback circuit for the probe of an d.c. type electrostatic voltmeter to reduce spacing sensitivity thereof. A variable gain amplifier is employed to control the amplitude of the a.c. signal output of a square wave oscillator in response to the potential sensed by the probe. The a.c. signal output drives a high voltage transformer, the output of which is rectified to provide a d.c. signal output matching the potential sensed by the probe. The d.c. output is returned to the probe housing to bias the housing to a potential equal to the potential read by the probe. A sample and hold circuit enables readout of the d.c. signal output.