Automatic developability sensing in electrophotographic printing

Claim 3

An apparatus according to claim 1, wherein said member includes: a substantially transparent prism; and a substantially transparent, electrically conductive layer adhering to one surface of said prism.

Claim 4

An apparatus according to claim 2, wherein said member includes means for electrically biasing said conductive layer to attract the charged particles thereto.

Claim 7

An apparatus according to claim 4, wherein said conductive layer adheres to the surface of said prism opposed from the right angle thereof.

Claim 8

An apparatus according to claim 5, wherein said transmitting means includes a light source transmitting light rays through said prism and said conductive layer onto the charged particles adhering thereto.

Claim 9

An apparatus according to claim 6, wherein said light source is secured to a surface of said prism other than the surface of said prism having said conductive layer adhering thereto.

Claim 10

An apparatus according to claim 6, wherein said detecting means includes a light sensor positioned to receive light rays internally reflected through said prism.

Claim 11

An apparatus according to claim 8, wherein said light sensor is secured to a surface of said prism.

Claim 12

An apparatus according to claim 8, wherein said conductive layer is a substantially uniform area adhering to the surface of said prism.

Claim 13

An apparatus according to claim 8, wherein the surface of said prism having said conductive layer adhering thereto is arranged in a pattern of conductive and non-conductive regions.

Claim 14

An apparatus according to claim 9, wherein said light source is a light emitting diode.

Claim 15

An apparatus according to claim 12, wherein said light sensor is a phototransistor.

Claim 16

An electrophotographic printing machine of the type having a developer roller for transporting a developer mixture comprising at least electrostatically charged particles closely adjacent to an electrostatic latent image recorded on a photoconductive surface so as to develop the latent image with the charged particles, wherein the improvement includes: a member, positioned closely adjacent to the developer roller, adapted to attract at least a portion of the charged particles to at least one surface thereof; means for transmitting a beam of energy through said member onto the charged particles attracted to the surface thereof, with the internal angle of incidence of the beam of energy being greater than the critical angle of incidence of said member; means for detecting the intensity of the beam of energy internally reflected through said member, said detecting means generating a signal indicative of the quantity of charged particles attracted to the surface of said member; and means, responsive to the signal generated by said detecting means, for controlling the concentration of charged particles in the developer mixture.

Claim 17

An electrophotographic printing machine of the type having a developer roller for transporting a developer mixture comprising at least electrostatically charged particles closely adjacent to an electrostatic latent image recorded on a photoconductive surface so as to develop the latent image with the charged particles, wherein the improvement includes: a member, positioned closely adjacent to the developer roller, adapted to attract at least a portion of the charged particles to at least one surface thereof; means for transmitting a beam of energy through said member onto the charged particles attracted to the surface thereof, with the internal angle of incidence of the beam of energy being greater than the critical angle of incidence of said member; means for detecting the intensity of the beam of energy internally reflected through said member, said detecting means generating a signal indicative of the quantity of charged particles attracted to the surface of said member; and means, responsive to the signal generated by said detecting means, for controlling the concentration of charged particles in the developer mixture.

Claim 18

A printing machine according to claim 14, wherein said member includes: a substantially transparent prism; and a substantially transparent, electrically conductive layer adhering to one surface thereof.

Claim 19

A printing machine according to claim 15, wherein said member includes means for electrically biasing said conductive layer to attract the charged particles thereto.

Claim 20

An electrophotographic printing machine of the type having a developer roller for transporting a developer mixture comprising at least electrostatically charged particles closely adjacent to an electrostatic latent image recorded on a photoconductive surface so as to develop the latent image with the charged particles, wherein the improvement includes: a substantially transparent, right triangular prism having equal opposed interior angles, said prism being positioned closely adjacent to the developer roller; a substantially transparent, electrically conductive layer adhering to one surface of said prism opposed from the developer roller; means for electrically biasing said conductive layer to attract the charged particles thereto; means for transmitting a beam of energy through said prism onto the charged particles attracted to said conductive layer; and means for detecting the intensity of the beam of energy internally reflected through said prism, said detecting means generating a signal indicative of the quantity of charged particles attracted to the surface of said conductive layer.

Claim 21

An electrophotographic printing machine of the type having a developer roller for transporting a developer mixture comprising at least electrostatically charged particles closely adjacent to an electrostatic latent image recorded on a photoconductive surface so as to develop the latent image with the charged particles, wherein the improvement includes: a substantially transparent, right triangular prism having equal opposed interior angles, said prism being positioned closely adjacent to the developer roller; a substantially transparent, electrically conductive layer adhering to one surface of said prism opposed from the developer roller; means for electrically biasing said conductive layer to attract the charged particles thereto; means for transmitting a beam of energy through said prism onto the charged particles attracted to said conductive layer; and means for detecting the intensity of the beam of energy internally reflected through said prism, said detecting means generating a signal indicative of the quantity of charged particles attracted to the surface of said conductive layer.

Claim 22

A printing machine according to claim 17, wherein said conductive layer adheres to the surface of said prism opposed from the right angle thereof.

Claim 23

A printing machine according to claim 18, wherein said transmitting means includes a light source transmitting light rays through said prism and said conductive layer onto the charged particles adhering thereto.

Claim 24

A printing machine according to claim 19, wherein said light source is secured to a surface of said prism other than the surface of said prism having said conductive layer adhering thereto.

Claim 25

A printing machine according to claim 19, wherein said detecting means includes a light sensor positioned to receive light rays internally reflected through said prism.

Claim 26

A printing machine according to claim 21, wherein said light sensor is secured to a surface of said prism.

Claim 27

A printing machine according to claim 21, wherein said conductive layer is a substantially uniform area adhering to the surface of said prism.

Claim 28

A printing machine according to claim 21, wherein the surface of said prism having said conductive layer adhering thereto is arranged in a pattern of conductive and non-conductive regions.

Claim 29

A printing machine according to claim 22, wherein said light source is a light emitting diode.

Claim 30

A printing machine according to claim 25, wherein said light sensor is a phototransistor.