Particle concentration detector

Claim 3

An apparatus as recited in claim 1, further including means, responsive to the electrical output signal from said detecting means, for dispensing toner particles into the mix of the development system to maintain the concentration thereof at substantially about the desired level.

Claim 4

An apparatus as recited in claim 1, wherein said reflecting means includes: insulating support means; a pair of conductive layers mounted on said support means, one of said pair of conductive layers being positioned in the first region of said reflecting means and the other of said pair of conductive layers being located in the second region thereof; and a resistance layer mounted on said support means connecting electrically said pair of conductive layers with one another.

Claim 5

An apparatus as recited in claim 3, wherein said electrical biasing means includes: a first voltage source electrically coupled to said one of said pair of conductive layers disposed in the first region of said reflecting means; and a second voltage source electrically coupled to said other of said pair of conductive layers disposed in the second region of said reflecting means, said second voltage source generating a greater potential than the potential generated by said first voltage source to create a current flow from said other of said pair of conductive layers to said one of said pair of conductive layers forming a potential pattern decreasing from the second region to the first region of said reflecting means.

Claim 6

An apparatus as recited in claim 4, wherein the development system includes magnetic means for depositing toner particles on the image-bearing member, said magnetic means being electrically biased to substantially the same potential as the potential generated by said first voltage source.

Claim 7

An apparatus as recited in claim 1, wherein: said generating means includes a light source; and said detecting means includes a photosensor positioned to receive the light rays reflected from said reflecting means.

Claim 8

An apparatus as recited in claim 1, wherein said reflecting means is mounted on the image-bearing member.

Claim 9

An electrophotographic printing machine of the type having a photoconductive member, and a development system employing a mix of carrier granules and toner particles, the toner particles being adapted to be deposited on an electrostatic latent image recorded on the photoconductive member, wherein the improvement includes: reflecting means disposed to attract toner particles thereto from the carrier granules of the mix; means for biasing electrically said reflecting means to produce a voltage pattern having a greater potential in a first region of said reflecting means than in a second region thereof; means for generating a beam of light ray, said reflecting means being in a light-receiving relationship with the beam of light rays so that a third region thereof having a pre-selected potential intermediate the potential of the first region and second region is illuminated by the beam of light rays; and means for detecting the intensity of the light rays reflected from said reflecting means, said detecting means producing an electrical output signal indicative of the intensity of light rays reflected from said reflecting means.

Claim 10

An electrophotographic printing machine of the type having a photoconductive member, and a development system employing a mix of carrier granules and toner particles, the toner particles being adapted to be deposited on an electrostatic latent image recorded on the photoconductive member, wherein the improvement includes: reflecting means disposed to attract toner particles thereto from the carrier granules of the mix; means for biasing electrically said reflecting means to produce a voltage pattern having a greater potential in a first region of said reflecting means than in a second region thereof; means for generating a beam of light ray, said reflecting means being in a light-receiving relationship with the beam of light rays so that a third region thereof having a pre-selected potential intermediate the potential of the first region and second region is illuminated by the beam of light rays; and means for detecting the intensity of the light rays reflected from said reflecting means, said detecting means producing an electrical output signal indicative of the intensity of light rays reflected from said reflecting means.

Claim 11

A printing machine as recited in claim 8, further including means, responsive to the electrical output signal from said detecting means, for dispensing toner particles into the mix of the development system to maintain the concentration thereof substantially at the desired level.

Claim 12

A printing machine as recited in claim 8, wherein said reflecting means includes: insulating support means; a pair of conductive layers mounted on said support means, one of said pair of conductive layers being positioned in the first region of said reflecting means and the other of said pair of conductive layers being located in the second region thereof; and a resistance layer mounted on said support means connecting electrically said pair of conductive layers with one another.

Claim 13

A printing machine as recited in claim 10, wherein said electrical biasing means includes: a first voltage source electrically coupled to said one of said pair of conductive layers positioned in the first region of said reflecting means; and a second voltage source electrically coupled to said other of said pair of conductive layers disposed in the second region of said reflecting means, said second voltage source generating a greater potential than the potential generated by sid first voltage source to create a current flow from said other of said pair of conductive layers to said one of said pair of conductive layers forming a potential pattern decreasing from the second region to the first region of said reflecting means.

Claim 14

A printing machine as recited in claim 11, wherein the development system includes magnetic means for depositing toner particles on the electrostatic latent image recorded on the photoconductive member, said magnetic means being electrically biased to substantially the same potential as the potential generated by said first voltage source.

Claim 15

A printing machine as recited in claim 8, wherein: said generating means includes a light source; and said detecting means includes a photosensor positioned to receive the light rays reflected from said reflecting means.

Claim 16

A printing machine as recited in claim 8, wherein said reflecting means is mounted on the photoconductive member.

Claim 17

An electrophotographic printing machine of the type having a photoconductive member, and a development system employing a mix of carrier granules and toner particles, the toner particles being adapted to be deposited on an electrostatic latent image recorded on the photoconductive member, wherein the improvement includes: means for forming on the photoconductive member a voltage gradient having the potential in a first region greater than the potential in a second region so as to attract toner particles thereto from the carrier granules of the mix; means for generating a beam of light rays, the voltage gradient formed on the photoconductive member being in a light-receiving relationship with the beam of light rays after toner particles are deposited thereon so that a portion thereof having a pre-selected potential intermediate the potential in the first region and the potential in the second region is illuminated by the beam of light rays; and means for detecting the intensity of the light rays reflected from the voltage gradient formed on the photoconductive member, said detecting means producing an electrical output signal indicative of the intensity of light rays reflected from the illuminated portion of the voltage gradient formed on the photoconductive member.

Claim 18

An electrophotographic printing machine of the type having a photoconductive member, and a development system employing a mix of carrier granules and toner particles, the toner particles being adapted to be deposited on an electrostatic latent image recorded on the photoconductive member, wherein the improvement includes: means for forming on the photoconductive member a voltage gradient having the potential in a first region greater than the potential in a second region so as to attract toner particles thereto from the carrier granules of the mix; means for generating a beam of light rays, the voltage gradient formed on the photoconductive member being in a light-receiving relationship with the beam of light rays after toner particles are deposited thereon so that a portion thereof having a pre-selected potential intermediate the potential in the first region and the potential in the second region is illuminated by the beam of light rays; and means for detecting the intensity of the light rays reflected from the voltage gradient formed on the photoconductive member, said detecting means producing an electrical output signal indicative of the intensity of light rays reflected from the illuminated portion of the voltage gradient formed on the photoconductive member.

Claim 19

A printing machine as recited in claim 15, further including means, responsive to the electrical output signal from said detecting means, for dispensing toner particles into the mix of the development system to maintain the concentration thereof at substantially about the desired level.

Claim 20

A printing machine as recited in claim 16, wherein the development system includes magnetic means for depositing toner particles on the voltage gradient formed on the photoconductive member, said magnetic means being electrically biased to substantially the same potential as the potential of the central region of the voltage gradient formed on the photoconductive member.

Claim 21

A printing machine as recited in claim 17, wherein: said generating means includes a light source; and said detecting means includes a photosensor positioned to receive the light rays reflected from the sample electrostatic latent image recorded on the photoconductive member.

Claim 22

A printing machine having a rotary journaled photoconductive member as recited in claim 18, wherein said recording means produces a sample electrostatic latent image having a voltage gradient wherein the potential of the voltage gradient decreases in the direction of rotation of the photoconductive member.

Claim 23

A printing machine as recited in claim 19, further including means, responsive to the electrical output signal from said detecting means, for dispensing toner particles into the mix of the development system to maintain the concentration thereof at substantially about the desired level.

Claim 24

A printing machine as recited in claim 20, wherein the development system includes magnetic means for depositing toner particles on the sample electrostatic latent image recorded on the photoconductive member.

Claim 25

A printing machine as recited in claim 21, wherein: said generating means includes a light source; and said detecting means includes a photosensor positioned to receive the light rays reflected from the sample electrostatic latent image recorded on the photoconductive member.