US3926627A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for making an electrophotographic image by use of photoconductive particles
Assignee: Fujifilm Holdings Corp
•
Filing: 1974-03-21
•
Granted: 1975-12-16
•
Expires: 1994-03-21
Abstract
Abstract An electric power image is obtained on either an insulating or conductive surface by use of photoconductive particles. Photoconductive particles are applied in a plurality of layers on a substrate having an insulating surface. The surface of the photoconductive particle layers is uniformly charged and exposed to imagewise light. By the exposure, the charges in the upper layers in the exposed area of the image are moved to the lower layers. The charges in the non-exposed area are neutralized by D.C. corona discharge in the reverse polarity or by A.C. corona discharge. The particles on the substrate are removed by air blow leaving only the particles in the lower layers of the non-exposed area which are electrostatically attracted by the insulating surface. The particle image can also be formed on a conductive substrate by applying precharged photoconductive particles on the conductive surface and simultaneously exposing the charged particle layers to the imagewise light and neutralizing the charges by A.C. corona discharge. In this case, a positive particle image is obtained from a positive light image.
Inventors
- 👤 Masakazu Iwasa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 01:44
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/22; G03G15/34; G03G15/342; Y; Y10; Y10S; Y10S430/00; Y10S430/001; Y10S430/101; Y10S430/102
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
128 words
A PROCESS FOR MAKING AN ELETROPHOTOGRAPHIC IMAGE BY USE OF PHOTOCONDUCTIVE PARTICLES COMPRISING THE STEPS OF: PROVIDING A PLURALITY OF LAYERS OF PHOTOCONDUCTIVE PARTICLES ON A SUBSTRATE HAVING AT LEAST AN INSULATING UPPER SURFACE, OF SAID PHOTOCONDUCTIVE PARTICLES. OF SAID PHOTOCONDUCTIVE PARTICLES. EXPOSING THE LAYERS OF PHOTOCONDUCTIVE PARTICLES TO IMAGEWISE LIGHT TO MOVE THE CHARGES IN THE UPPER PART OF THE LAYERS TO THE LOWER PART THEREOF IN THE AREA EXPOSED TO THE LIGHT, NEUTRALIZING FROM A CHARGING MEANS EXTERNAL TO THE SUBSTRATE THE CHARGES ON THE OUTER SURFACE OF THE LAYERS IN THE AREA NOT EXPOSED TO THE LIGHT, AND REMOVING SAID PHOTOCONDUCTIVE PARTICLES FROM THE SURFACE OF SAID RECORDING MEDIUM TO LEAVE THE PARTICLES WHICH RECEIVED THE CHARGE MOVED FROM THE UPPER PART OF THE LAYERS.
Claim 2
Dependent Claim
128 words
A PROCESS FOR MAKING AN ELETROPHOTOGRAPHIC IMAGE BY USE OF PHOTOCONDUCTIVE PARTICLES COMPRISING THE STEPS OF: PROVIDING A PLURALITY OF LAYERS OF PHOTOCONDUCTIVE PARTICLES ON A SUBSTRATE HAVING AT LEAST AN INSULATING UPPER SURFACE, OF SAID PHOTOCONDUCTIVE PARTICLES. OF SAID PHOTOCONDUCTIVE PARTICLES. EXPOSING THE LAYERS OF PHOTOCONDUCTIVE PARTICLES TO IMAGEWISE LIGHT TO MOVE THE CHARGES IN THE UPPER PART OF THE LAYERS TO THE LOWER PART THEREOF IN THE AREA EXPOSED TO THE LIGHT, NEUTRALIZING FROM A CHARGING MEANS EXTERNAL TO THE SUBSTRATE THE CHARGES ON THE OUTER SURFACE OF THE LAYERS IN THE AREA NOT EXPOSED TO THE LIGHT, AND REMOVING SAID PHOTOCONDUCTIVE PARTICLES FROM THE SURFACE OF SAID RECORDING MEDIUM TO LEAVE THE PARTICLES WHICH RECEIVED THE CHARGE MOVED FROM THE UPPER PART OF THE LAYERS.
Claim 3
Dependent Claim
28 words
A process for making an electrophotographic image as defined in claim 1 wherein said uniform charging step is conducted by use of a direct current corona charging means.
Claim 4
Dependent Claim
24 words
A process for making an electrophotographic image as defined in claim 1 wherein said uniform charging step and said exposing step are conducted simultaneously.
Claim 5
Dependent Claim
31 words
A process for making an electrophotographic image as define in claim 1 wherein said step of removing the photoconductive particles is performed by blowing air against the surface of the substrate.
Claim 6
Dependent Claim
22 words
A process for making an electrophotographic image as defined in claim 1 wherein said insulating substrate is deisposed on a conductive base
Claim 7
Dependent Claim
18 words
A process for making an electrophotographic image as defined in claim 1 wherein said substrate is entirely insulating.
Claim 8
Dependent Claim
39 words
A process for making an electrophotographic image as defined in claim 6 wherein said uniform charging step is conducted by used of pair of D.C. corona charging means of opposite polarities respectively disposed on opposite sides of said substrate.
Claim 9
Dependent Claim
36 words
A process for making an electrophotographic image as defined in claim 7 wherein said neutralizing step is conducted by use of a pair of A.C. corona charging means respectively located on opposite sides of the substrate.
Claim 10
Dependent Claim
55 words
A process for making an electrophotographic image as defined in claim 7 wherein said neutralizing step is conducted by use of a pair of D.C. corona charging means respectively disposed on opposite sides of said substrate and of reverse polarities to those of said D.C. corona charging means used for uniformly charging the photoconductive layers.
Claim 11
Dependent Claim
117 words
A process for making an electrophotographic image comprising the steps of providing a plurality of layers of charged photoconductive particles on a substrate; exposing the layers of photoconductive particles to imagewise light; neutralizing from a charging means external to the substrate all of the charges in all of the layers in the area exposed to light and substantially only the charges in the upper part of the layers in the area not exposed to light to form at the lower part of said layers an electrostatic latent image; and removing said photoconductive particles from said substrate to leave the charged particles not neutralized in the lower part of said layers in the area not exposed to light.
Claim 12
Dependent Claim
117 words
A process for making an electrophotographic image comprising the steps of providing a plurality of layers of charged photoconductive particles on a substrate; exposing the layers of photoconductive particles to imagewise light; neutralizing from a charging means external to the substrate all of the charges in all of the layers in the area exposed to light and substantially only the charges in the upper part of the layers in the area not exposed to light to form at the lower part of said layers an electrostatic latent image; and removing said photoconductive particles from said substrate to leave the charged particles not neutralized in the lower part of said layers in the area not exposed to light.
Claim 13
Dependent Claim
54 words
A process for making an electrophotographic image as defined in claim 10 wherein said step of providing a plurality of layers of charged photoconductive particles on a recording medium comprises charging a number of photoconductive particles in a predetermined polarity, and applying the charged particles in a plurality of layers on a recording medium.
Claim 14
Dependent Claim
27 words
A process for making an electrophotographic image as defined in claim 11 wherein the uniform charging step and the step of applying the particles are conducted simultaneously.
Claim 15
Dependent Claim
23 words
A process for making an electrophotographic image as defined in claim 10 wherein said exposing step and said neutralizing step are conducted simultaneously.
Claim 16
Dependent Claim
17 words
A process for making an electrophotographic image as defined in claim 13 wherein said substrate is conductive.
Claim 17
Dependent Claim
17 words
A process for making an electrophotographic image as defined in claim 13 wherein said substrate is conductive.
Claim 18
Dependent Claim
31 words
A process for making an electrophotographic image as defined in claim 10 wherein said step of removing the photoconductive particles is performed by blowing air against the surface of the substrate.
Claim 19
Dependent Claim
25 words
A process for making an electrophotographic image as defined in claim 10 wherein said insulating substrate is disposed on a conductive base plate attached thereto.
Claim 20
Dependent Claim
18 words
A process for making an electrophotographic image as defined in claim 10 wherein said substrate is entirely insulating.
Claim 21
Dependent Claim
38 words
A process for making an electrophotographic image as defined in claim 18 wherein a D.C. corona charging means charges the back side of the insulating substrate to a polarity opposite that of the charges imparted to the particles.
Claim 22
Dependent Claim
36 words
A process for making an electrophotographic image as defined in claim 19 wherein said neutralizing step is conducted by use of a pair of A.C. corona charging means respectively located on opposite sides of the substrate.
Claim 23
Dependent Claim
55 words
A process for making an electrophotographic image as defined in claim 19 wherein said neutralizing step is conducted by use of a pair of D.C. corona charging means respectively disposed on opposite sides of said substrate and of reverse polarities to those of said D.C. corona charging means used for uniformly charging the photoconductive layers.
Claim 24
Dependent Claim
134 words
A process for making an electrophotographic image comprising the steps of providing a plurality of layers of photoconductive particles on a substrate; providing a uniform charge to at least the upper layer of said photoconductive particles; exposing the layers of photoconductive particles to imagewise light; neutralizing at least the charges on the outer surface of the layers in the area not exposed to light with neutralizing charges of a polarity opposite to that of the charges on the outer surfaces, said neutralizing charges bEing provided from a source external to said substrate to form at the lower part of said layers an electrostatic latent image corresponding to said imagewise light; and removing at least those photoconductive particles in the non-latent image area from said substrate to leave the particles in said latent image area.
Claim 25
Dependent Claim
134 words
A process for making an electrophotographic image comprising the steps of providing a plurality of layers of photoconductive particles on a substrate; providing a uniform charge to at least the upper layer of said photoconductive particles; exposing the layers of photoconductive particles to imagewise light; neutralizing at least the charges on the outer surface of the layers in the area not exposed to light with neutralizing charges of a polarity opposite to that of the charges on the outer surfaces, said neutralizing charges bEing provided from a source external to said substrate to form at the lower part of said layers an electrostatic latent image corresponding to said imagewise light; and removing at least those photoconductive particles in the non-latent image area from said substrate to leave the particles in said latent image area.
Claim 26
Dependent Claim
115 words
A process as in claim 22 where said substrate has at least an insulating upper surface and where said uniform charge is substantially restricted to the upper part of said layers of photoconductive particles, said exposing step causing the charges in the area exposed to light to move to the lower part of said layers and said neutralizing step occurring after said exposing step and not affecting said charges in the lower part so that said charges in the lower part hold their associated photoconductive particles to the substrate as the non-latent image area photoconductive particles are removed whereby a visible image corresponding to a reversal of said light image is formed on said substrate.
Claim 27
Dependent Claim
26 words
A process as in claim 23 where said substrate is disposed on a conductive lower layer, said conductive layer being grounded during said uniform charging step.
Claim 28
Dependent Claim
49 words
A process as in claim 23 where said substrate is entirely insulative, said photoconductive particles being disposed on one side of said substrate and charges having a polarity opposite that of said uniform charge being uniformly applied to the side opposite said one side during said uniform charging step.
Claim 29
Dependent Claim
93 words
A process as in claim 22 where substantially all of said layers of photoconductive particles are provided with said uniform charge, said exposing and neutralizing steps occurring simultaneously to neutralize the charges in the area exposed to light in all of said layers so that the reamining charges in the lower part of the layers not exposed to light hold their associated photoconductive particles to the substrate as the non-latent image area particles are removed whereby a visible image corresponding to a positive reproduction of said light image is formed on said substrate.
Claim 30
Dependent Claim
11 words
A process as in claim 26 where said substrate is conductive.
Claim 31
Dependent Claim
29 words
A process as in claim 26 where said substrate comprises an insulative layer disposed on a conductive lower layer, said conductive layer being grounded during said uniform charging step.
Claim 32
Dependent Claim
49 words
A process as in claim 26 where said substrate is entirely insulative, said photoconductive particles being disposed on one side of said substrate and charges having a polarity opposite that of said uniform charge being uniformly applied to the side opposite said one side during said uniform charging step.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-15 | 1979-06-16 | 1979-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-15 | 1983-06-16 | 1983-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-15 | 1987-06-16 | 1987-12-16 | $7700.00 | Window Closed / Lapsed |