US 7,734,225 B2 · Tri-level tandem xerographic architecture using reduced strength toner

Abstract

A xerographic system and method use a tri-level development process in which at least one xerographic imaging unit includes a photoreceptor and a pair of developer units. A first developer unit includes a full strength toner of a given color and a second developer unit includes a reduced strength toner of the same or substantially the same color. By use of the tri-level process, excellent color-to-color registration can be achieved for each processed color separation. Moreover, by use of two strengths of the same colorant, a tighter control of a tone reproduction curve can be achieved. Additional xerographic imaging units can include a developer unit that provides spot color, custom color or specialty color capabilities. Additional benefits and gamut expansion can be achieved through use of a tandem architecture. A preferred implementation uses a four drum, eight color tandem architecture with full strength and reduced strength toners formulations of Cyan, Magenta, Yellow, and Black (CYMK) colorant.

Claims20

Dependent claims

A xerographic printing method, comprising:

uniformly charging a photoreceptor of a first tri-level xerographic imaging unit to a predetermined voltage;
creating tri-level electrostatic images including CAD image areas and DAD image areas having different voltage levels, respectively on the photoreceptor;
developing the CAD image areas and DAD image areas with a first full strength toner of a first color and a first reduced strength toner of substantially the same first color to form a first composite separation image of a desired image;
transferring the first composite separation image onto a substrate.

1 more element

A xerographic machine, comprising:

a first photoreceptor associated with a first tri-level xerographic imaging unit including
a charging device for charging the first photoreceptor to a predetermined voltage;
a ROS for obtaining tri-level electrostatic images including CAD image areas and DAD image areas on the first photoreceptor;
and
first and second developer units for developing the CAD image areas and the DAD image areas with a first full strength colorant toner of a first color from one of the developer units and a first reduced strength colorant toner of substantially the same first color from the other of the developer units, wherein one of the toners is developed in the CAD image areas and the other toner is developed in the DAD image areas to form a first composite color separation of a desired image on the first photoreceptor;
a second photoreceptor associated with a second tri-level xerographic imaging unit including
a charging device for charging the second photoreceptor to a predetermined voltage;
a ROS for obtaining tri-level electrostatic images including CAD image areas and DAD image areas on the second photoreceptor;
and
third and fourth developer units for developing the CAD image areas and the DAD image areas with a second full strength colorant toner of a first color from one of the third and fourth developer units and a second reduced strength colorant toner of substantially the same second color from the other of the third and fourth developer units, wherein one of the toners is developed in the CAD image areas and the other toner is developed in the DAD image areas to form a second composite color separation of a desired image on the second photoreceptor;
and
a transfer member that transfers the first and second color separations in registration onto an intermediate transfer member.

9 more elements

Dependencies are inferred from the claim text.

Tri-level tandem xerographic architecture using reduced strength toner

Life of this patent

Tri-level tandem xerographic architecture using reduced strength toner

Life of this patent

Abstract

Claims20