Liquid Electro-Photographic Printing Color Registration
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Solution Overview
Problem
Conventional liquid electro-photographic (LEP) printing processes face challenges in accurately aligning successive ink layers, leading to color plane registration errors and poor ink transferability and adhesion due to drying issues on the intermediate transfer member.
Innovation Solution
A new '4-1-1' LEP printing process where color ink layers are applied successively on the photoconductor and transferred as a single composite to the intermediate transfer member, optimizing the process to minimize registration errors and maintain high color quality by avoiding excessive drying and allowing the transfer member to recover between cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If successive ink layers are transferred individually from photoconductor to intermediate transfer member, then each layer can be processed separately, but color plane registration errors occur and transferability deteriorates due to drying issues
Solution Approach 1:
The patent combines multiple ink layers (CMYK) into a single composite ink image on the photoconductor before transfer. All four color layers are developed and transferred together in one operation to the intermediate transfer member, eliminating sequential transfer operations and ensuring perfect color registration while maintaining optimal transferability through simultaneous processing.
2Reliability
If intermediate transfer member is heated to dry ink film, then transferability improves, but color quality degrades due to excessive drying
Solution Approach 1:
The patent optimizes the intermediate transfer member temperature parameters to achieve sufficient drying for good transferability while preventing excessive drying that would degrade color quality. The temperature is controlled within a specific range that evaporates carrier liquid adequately without over-drying the toner particles, preserving color fidelity.
3Productivity
If intermediate transfer member processes continuously, then productivity increases, but registration accuracy decreases due to lack of recovery time
Solution Approach 1:
The patent implements periodic recovery cycles for the intermediate transfer member where the drum is allowed to return to ambient temperature between printing operations. This periodic cooling prevents thermal accumulation and maintains registration accuracy over extended printing sequences, enabling sustained high-quality output without continuous overheating issues.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach minimizes color plane registration errors, ensures good ink transferability and adhesion, and maintains high color quality by developing ink layers on a cool photoconductor and transferring them to a hot intermediate transfer member where the carrier liquid evaporates, fusing toner particles for improved substrate adhesion.
Implementation Method 1
an electrostatic pattern of the desired printed image is formed on a photoconductor
Implementation Method 2
This latent image is developed into a visible image by applying a thin layer of LEP ink to the patterned photoconductor
Implementation Method 3
The ink image is transferred from the photoconductor to a heated intermediate transfer member, evaporating much of the carrier liquid to dry the ink film
Implementation Method 4
The semi-solid ink film is then pressed on to the cooler print substrate and 'frozen' in place at a nip between the intermediate transfer member and the substrate
Data Source
Figure 1
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AI summary
In one example, a printing process includes: forming a first latent image on a photoconductor (24); applying a first LEP ink (30) to the photoconductor to develop the first latent image into a first ink image; forming a second latent image having a first part on the first ink image and a second part on the photoconductor; and applying a second LEP ink (32, 34, 36) to the first ink image and to the photoconductor to develop the second latent image into a second ink image and form a composite on the photoconductor in which some of the second ink image overlaps some of the first ink image.