Single pass, multicolor contact electrostatic printing system

An imaging process for effecting single-pass, multicolor printing of a color image, comprising the steps of:

• providing a plurality of contact electrostatic printing engines operable in serial fashion upon a copy substrate, wherein each contact electrostatic printing engine images and develops a respective electrostatic latent image representative of a component of the color image, and subsequently transfers the developed component image to the copy substrate as the copy substrate is engaged by each contact electrostatic printing engine and proceeds in a single pass through the imaging system;
• providing, in at least one of said contact electrostatic printing engines, a first movable member for having an electrostatic latent image formed thereon including image areas defined by a first voltage potential and non-image areas defined by a second voltage potential;
• providing a second movable member for having a layer of liquid developing material coated thereon and developing material comprising toner particles and a liquid carrier;
• forming a process nip by operative engagement of said first movable member and said second movable member, said process nip being defined by a nip entrance, a nip exit and a nip gap therebetween;
• positioning the layer of liquid developing material in pressure contact with said first movable member in said process nip, wherein the electrostatic latent image on said first member generates imagewise electric fields across the layer of liquid developing material in said process nip;
• imagewise developing said developing material in said nip gap to form a developed image corresponding to said image areas, and a background image corresponding to said non-image areas, said developed image and said background image each having the thickness greater than one-half the nip gap;
• and
• imagewise separating the layer of liquid developing material at said nip exit.

An imaging system for effecting single-pass, multicolor printing of a color image, comprising:

• a plurality of contact electrostatic printing engines operable in serial fashion upon a copy substrate, wherein each contact electrostatic printing engine includes means for imaging and developing a respective electrostatic latent image representative of a component of the color image, and means for subsequently transferring the developed component image to the copy substrate as the copy substrate is engaged by each contact electrostatic printing engine and proceeds in a single pass through the imaging system, wherein at least one of the contact electrostatic printing engines further comprises:
• image bearing member to form a marking material layer thereon adjacent the electrostatic latent image on said imaging member;
• a charging source for selectively delivering charges to the marking material layer in an image-wise manner responsive to the electrostatic latent image on said image bearing member to form a secondary latent image in the marking material layer having image and non-image areas corresponding to the electrostatic latent image on said imaging member;
• and
• separator member for selectively separating portions of the marking material layer in accordance with the secondary latent image in the marking material layer to create a developed image corresponding to the electrostatic latent image formed on said image bearing member.

An imaging system for effecting single-pass, multicolor printing of a color image, comprising:

• a plurality of contact electrostatic printing engines operable in serial fashion upon a copy substrate, wherein each contact electrostatic printing engine includes means for imaging and developing a respective electrostatic latent image representative of a component of the color image, and means for subsequently transferring the developed component image to the copy substrate as the copy substrate is engaged by each contact electrostatic printing engine and proceeds in a single pass through the imaging system, wherein at least one of the contact electrostatic printing engines further comprises:
• an image bearing member for having an electrostatic latent image formed thereon, said image bearing member having a surface capable of supporting toner particles;
• an imaging device for generating the electrostatic latent image on said image bearing member, wherein the electrostatic latent image includes image areas defined by a first charge voltage and non-image areas defined by a second charge voltage distinguishable from the first charge voltage;
• a toner supply apparatus for depositing toner particles on the surface of said imaging member to form a toner layer thereon adjacent the electrostatic latent image on said image bearing member;
• a biased member for inducing air breakdown to create an electrical discharge in the vicinity of the toner layer on the latent image on the image bearing member, wherein the electrical discharge selectively delivers charged ions to the toner layer in response to the electrostatic latent image on said image bearing member to form a secondary latent image in the toner layer having image and non-image areas corresponding to the electrostatic latent image on said image bearing member;
• and
• a separator member for selectively separating and transferring portions of the toner layer thereto in accordance with the secondary latent image in the toner layer to create a developed image corresponding to the electrostatic latent image formed on said image bearing member.