Nondestructive readout of a latent electrostatic image formed on an insulating material

The method of claim 27 and wherein the reference electrode is positioned such that the insulator is between the reference electrode and the semiconductor.

Apparatus for use in reading out accumulated charges on an insulator without destroying the accumulated charges, the apparatus comprising:

• a. a semiconductor, said semiconductor being conductive in the dark and being disposed in relatively close proximity to but not in contact with the accumulated charges on the insulator such that a depletion layer related to the accumulated charges on the insulator is induced in the semiconductor,
• b. a reference electrode, and
• c. means for scanning said semiconductor with a beam of light, the beam of light producing an electrical signal between the semiconductor and the reference electrode corresponding to charges induced in the semiconductor.

A method of reading out accumulated charges in a first layer of insulating material, said first layer of insulating material being on top of a second layer of insulating material, said second layer of insulating material being on top of a layer of semiconductor material, said layer of semiconductor material being conductive in the dark and being on the top surface of a substrate, said accumulated charges in said first layer of insulating material inducing a depletion layer in said layer of semiconductor material, said method comprising:

• a. providing a reference electrode, and
• b. measuring the surface photovoltage between the layer of semiconductor material and the reference electrode.

A method of reading out accumulated charges on a sheet of insulating material without destroying the accumulated charges, the method comprising:

• a. providing a sheet of semiconductor material which is conductive in the dark,
• b. positioning the sheet of insulating material relative to the sheet of semiconductor materials such that the accumulated charges on the sheet of insulating material are in close proximity to but not in contact with the sheet of semiconductor material, the accumulated charges on the sheet of insulating material including a depletion layer in the sheet of semiconductor material, the accumulated charges in the depletion layer in the sheet of semiconductor material being related to the accumulated charges in the sheet of insulating material, and
• c. detecting the magnitude and location of the accumulated charges in the sheet of semiconductor material.

A photoreceptor comprising:

• a. a semiconductor,
• b. a protective insulator on the semiconductor,
• c. a photoconductive insulator on the protective insulator.

A photoreceptor comprising:

• a. a wafer of semiconductor material, having a top surface and a bottom surface,
• b. a protective insulating layer on the top surface of the wafer, and
• c. a metal electrode above and spaced apart from the protective insulating layer.