Multiple copy electrophotographic reproduction process

Claim 2

A PROCESS FOR ELECTROPHOTOGRAPHICALLY PRODUCING MORE THAN THREE COPIES PER EXPOSURE TO A LIGHT PATTERN OF ACTINIC RADIATION COMPRISING: A. PROVIDING A PHOTOCONDUCTIVE SHEET COMPRISING A BASE HAVING A COATING THEREON COMPRISING: I. PHOTOCONDUCTIVE TITANIUM DIOXIDE HAVING A CHARACTERISTIC RELAXATION TIME OF LESS THAN ABOUT 9 MINUTES AND BEING PRESENT TO THE EXTENT OF ABOUT 40% TO ABOUT 60% BY VOLUME OF SAID COATING; II. AN INSULATING BINDER PROVIDING A MATRIX FOR SAID PHOTOCONDUCTIVE TITANIUM DIOXIDE HAVING AN ACID NUMBER BELOW 70; AND III. FROM ABOUT 0.1 X 10**-6 TO ABOUT 15 X 10**-6 EQUIVALENTS PER SQUARE METER OF TOTAL PHOTOCONDUCTIVE TITANIUM DIOXIDE SURFACE OF AT LEAST ONE ORGANIC ACID OR ORGANIC ACID SALT DECAY RETARDER HAVING AT LEAST 6 CARBON ATOMS PER MOLECULE; B. EXPOSING SAID PHOTOCONDUCTIVE SHEET TO A LIGHT PATTERN TO PRODUCE A LATENT IMAGE ON SAID PHOTOCONDUCTIVE SHEET CORRESPONDING TO SAID LIGHT PATTERN; C. ELECTROGRAPHICALLY DEVELOPING SAID LATENT IMAGE; D. TRANSFERRING THE DEVELOPED IMAGE TO A RECEPTOR SHEET; AND E. SEQUENTIALLY REPEATING STEPS (C) AND (D) AT LEAST 3 TIMES IN THE ABSENCE OF FURTHER EXPOSURE ACCORDING TO STEP (B) WHEREBY AT LEAST FOUR RECEPTOR SHEETS ARE PROVIDED EACH DEFINING A DEVELOPED IMAGE OF SUBSTANTIALLY SIMILAR CONTRAST CORRESPONDING TO SAID LIGHT PATTERN ARE PRODUCED.

Claim 3

A process for electrophotographically producing more than three copies per exposure to a light pattern of actinic radiation comprising: a. providing a photoconductive sheet comprising a base having a coating thereon comprising: i. photoconductive titanium dioxide having a characteristic relaxation time of less than about 9 minutes and being present to the extent of about 40% to about 60% by volume of Said coating; ii. an insulating binder providing a matrix for said photoconductive titanium dioxide having an acid number below 70; and iii. from about 0.1 X 10 6 to about 15 X 10 6 equivalents per square meter of total photoconductive titanium dioxide surface of at least one organic acid or organic acid salt decay retarder having at least 6 carbon atoms per molecule; b. exposing said photoconductive sheet to a light pattern to produce a latent image on said photoconductive sheet, said latent image being a differentially conductive pattern corresponding to said light pattern; c. uniformly contacting said photoconductive sheet bearing said latent image with an electrically conductive applicator bearing on the surface thereof electrically conductive developer powder; d. coincident with said contacting applying a direct current electrical potential between said photoconductive sheet and said applicator whereby an electrical field is created between said photoconductive sheet and said applicator; e. separating said applicator from said photoconductive sheet while maintaining said electrical field whereby said developer powder is deposited on said photoconductive sheet in a pattern corresponding to said light pattern; f. transferring said deposited developer powder from said photoconductive sheet to a receptor surface; and g. sequentially repeating steps (c)-(f) at least three more times, whereby at least four receptor sheets are provided each defining a developed image of substantially similar contrast corresponding to said light pattern are produced.

Claim 4

A process for electrophotographically producing more than three copies per exposure to a light pattern of actinic radiation comprising: a. providing a photoconductive sheet comprising a base having a coating thereon comprising: i. photoconductive titanium dioxide having a characteristic relaxation time of less than about 9 minutes and being present to the extent of about 40% to about 60% by volume of Said coating; ii. an insulating binder providing a matrix for said photoconductive titanium dioxide having an acid number below 70; and iii. from about 0.1 X 10 6 to about 15 X 10 6 equivalents per square meter of total photoconductive titanium dioxide surface of at least one organic acid or organic acid salt decay retarder having at least 6 carbon atoms per molecule; b. exposing said photoconductive sheet to a light pattern to produce a latent image on said photoconductive sheet, said latent image being a differentially conductive pattern corresponding to said light pattern; c. uniformly contacting said photoconductive sheet bearing said latent image with an electrically conductive applicator bearing on the surface thereof electrically conductive developer powder; d. coincident with said contacting applying a direct current electrical potential between said photoconductive sheet and said applicator whereby an electrical field is created between said photoconductive sheet and said applicator; e. separating said applicator from said photoconductive sheet while maintaining said electrical field whereby said developer powder is deposited on said photoconductive sheet in a pattern corresponding to said light pattern; f. transferring said deposited developer powder from said photoconductive sheet to a receptor surface; and g. sequentially repeating steps (c)-(f) at least three more times, whereby at least four receptor sheets are provided each defining a developed image of substantially similar contrast corresponding to said light pattern are produced.