Process for producing electrostatographic prints

Claim 2

A process for producing positive and negative prints from both positive and negative originals, comprising: forming an electrostatic latent image from said original; developing the electrostatic latent image with a developer having only one type of finely divided toner particles and only one type of carrier therefor the carrier particles being larger than the toner particles, at least the surface of said carrier comprising material which is capable of imparting both a negative and a positive charge to said toner whereby said toner electrostatically adhering to said carrier is both negatively and positively charged on said carrier, whereby toner of one polarity is deposited in the image area and toner of the other polarity is deposited in at least the background area immediately adjacent the image area without providing two or more types of toner and/or carrier particles; and transferring toner of one polarity to a receiving surface to produce a positive or negative print.

Claim 3

A process for producing positive and negative prints from both positive and negative originals, comprising: forming an electrostatic latent image from said original; developing the electrostatic latent image with a developer having only one type of finely divided toner particles and only one type of carrier therefor the carrier particles being larger than the toner particles, at least the surface of said carrier comprising a material which is an electret capable of imparting both a negative and a positive charge to said toner whereby said toner electrostatically adhering to said carrier is both negatively and positively charged on said carrier, whereby toner of one polarity is deposited in the image area and toner of the other polarity is deposited in at least the background area immediately adjacent the image area without providing two or more types of toner and/or carrier particles; and transferring toner of one polarity to a receiving surface to produce a positive or negative print.

Claim 4

A process for producing positive and negative prints from both positive and negative originals, comprising: forming an electrostatic latent image from said original; developing the electrostatic latent image with a developer having only one type of finely divided toner particles and only one type of carrier therefor the carrier particles being larger than the toner particles, at least the surface of said carrier comprising a material which is an electret capable of imparting both a negative and a positive charge to said toner whereby said toner electrostatically adhering to said carrier is both negatively and positively charged on said carrier, whereby toner of one polarity is deposited in the image area and toner of the other polarity is deposited in at least the background area immediately adjacent the image area without providing two or more types of toner and/or carrier particles; and transferring toner of one polarity to a receiving surface to produce a positive or negative print.

Claim 5

A process for producing positive and negative prints from both positive and negative originals, in accordance with claim 2 wherein the material which is an electret is calcium titanate.

Claim 6

A process for producing positive and negative prints from both positive and negative originals, comprising: forming an electrostatic latent image from said original; developing the electrostatic latent image with a developer having only one type of finely divided toner particles and only one type of carrier therefor the carrier particles being larger than the toner particles, at least the surface of the carrier being formed of at least two incompatible materials one of which is triboelectrically negative with respect to said toner and the other of which is triboelectrically positive with respect to said toner, and said incompatible materials are capable of imparting both a negative and a positive charge to said toner, whereby said toner electrostatically adhering to said carrier is both negatively and positively charged on said carrier, immediately adjacent the image area without providing two or more types of toner and/or carrier particles; and transferring toner of one polarity to a receiving surface to produce a positive or negative print.

Claim 7

A process for producing positive and negative prints from both positive and negative originals, comprising: forming an electrostatic latent image from said original; developing the electrostatic latent image with a developer having only one type of finely divided toner particles and only one type of carrier therefor the carrier particles being larger than the toner particles, at least the surface of the carrier being formed of at least two incompatible materials one of which is triboelectrically negative with respect to said toner and the other of which is triboelectrically positive with respect to said toner, and said incompatible materials are capable of imparting both a negative and a positive charge to said toner, whereby said toner electrostatically adhering to said carrier is both negatively and positively charged on said carrier, immediately adjacent the image area without providing two or more types of toner and/or carrier particles; and transferring toner of one polarity to a receiving surface to produce a positive or negative print.

Claim 8

A process for producing positive and negative prints from both positive and negative originals, in accordance with claim 4 where said at least two materials are present on the surface of said carrier in a domain size which is at least about the average particle size of said toner.

Claim 9

A process for producing positive and negative prints from both positive and negative originals, in accordance with claim 4 wherein said carrier is a coated carrier said at least two materials forming the coating of said carrier.

Claim 10

A process for producing positive and negative prints from both positive and negative originals in accordance with claim 4 wherein said carrier is an uncoated carrier and said uncoated carrier is comprised of said at least two materials.

Claim 11

A process for producing positive and negative prints from both positive and negative originals in accordance with claim 7 wherein the carrier comprises barium ferrite dispersed in rubber.

Claim 12

A process for producing positive and negative prints from both positive and negative originals in accordance with claim 7 wherein the carrier comprises calcium titanate dispersed in selenium.

Claim 13

A process for producing positive and negative prints from both positive and negative originals, comprising: forming an electrostatic latent image from said original; developing said electrostatic latent image with a developer having both negatively and positively charged toner and carrier therefor, the toner being charged positively by the carrier and the toner being charged negatively by the carrier, whereby toner of one polarity is deposited in the image area and toner of the other polarity is deposited in at least the background area immediately adjacent the image area, and transferring toner of one polarity to a receiving surface to produce a positive or negative print.

Claim 14

A process for producing positive and negative prints from both positive and negative originals, comprising: forming an electrostatic latent image from said original; developing said electrostatic latent image with a developer having both negatively and positively charged toner and carrier therefor, the toner being charged positively by the carrier and the toner being charged negatively by the carrier, whereby toner of one polarity is deposited in the image area and toner of the other polarity is deposited in at least the background area immediately adjacent the image area, and transferring toner of one polarity to a receiving surface to produce a positive or negative print.

Claim 15

A process for producing positive and negative prints from both positive and negative originals, comprising: forming an electrostatic latent image from said original developing said electrostatic latent image with a developer having both negatively and positively charged toner, the developer comprising an electrostatographic developer carrier and two different toners one of which is positively charged by said carrier and the other of which is negatively charged by said carrier, whereby toner of one polarity is deposited in the image area and toner of the other polarity is deposited in at least the background area immediately adjacent the image area; and transferring toner of one polarity to a receiving surface to produce a positive or negative print.

Claim 16

A process for producing positive and negative prints from both positive and negative originals, comprising: forming an electrostatic latent image from said original developing said electrostatic latent image with a developer having both negatively and positively charged toner, the developer comprising an electrostatographic developer carrier and two different toners one of which is positively charged by said carrier and the other of which is negatively charged by said carrier, whereby toner of one polarity is deposited in the image area and toner of the other polarity is deposited in at least the background area immediately adjacent the image area; and transferring toner of one polarity to a receiving surface to produce a positive or negative print.

Claim 17

A process for producing positive and negative prints from both positive and negative originals, comprising: forming an electrostatic latent image from said original; developing said electrostatic latent image with a developer having both negatively and positivey charged toner, the developer comprising two different electrostatographic developer carriers and a single toner, one carrier charging said toner positively and the other carrier charging said toner negatively, whereby toner of one polarity is deposited in the image area and toner of the other polarity is deposited in at least the background area immediately adjacent the image area; and transferring toner of one polarity to a receiving surface to produce a positive or negative print.

Claim 18

A process for producing positive and negative prints from both positive and negative originals, comprising: forming an electrostatic latent image from said original; developing said electrostatic latent image with a developer having both negatively and positivey charged toner, the developer comprising two different electrostatographic developer carriers and a single toner, one carrier charging said toner positively and the other carrier charging said toner negatively, whereby toner of one polarity is deposited in the image area and toner of the other polarity is deposited in at least the background area immediately adjacent the image area; and transferring toner of one polarity to a receiving surface to produce a positive or negative print.

Claim 19

The process of claim 10 wherein said original is a positive original and a positive copy is produced by electrostatically transferring toner to the receiving surface by a charge of the same polarity as a charge placed on an imaging surface on which said electrostatic latent image is formed.

Claim 20

The process of claim 10 wherein said original is a positive original and a negative copy is produced by electrostatically transferring toner to the receiving surface by a charge of a polarity opposite to that of a charge placed on an imaging surface on which the electrostatic latent image is formed.

Claim 21

The process of claim 10 wherein said original is a negative original and a negative copy is produced by electrostatically transferring toner to the receiving surface by a charge of the same polarity as a charge placed on an imaging surface on which said electrostatic latent image is formed.

Claim 22

The process of claim 10 wherein said original is a negative original and a positive copy is produced by electrostatically transferring toner to the receiving surface by a charged of a polarity opposite to that of a charge placed on an imaging surface on which the electrostatic latent image is formed.

Claim 23

A process for producing positive and negative prints from both positive and negative originals in accordance with claim 4 wherein said coating comprises calcium titanate dispersed in selenium.