Liquid Electrophotographic Printer Selective Compression
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Solution Overview
Problem
In liquid electrophotographic printing, the one shot color process leads to over-drying of the first separation layer due to prolonged exposure on a heatable transfer element, resulting in poor transferability and adhesion to the print substrate, limiting media gamut.
Innovation Solution
A compressive element is selectively engaged to remove a portion of carrier liquid from subsequent layers while retaining it in the first layer, and the air supply is controlled to adjust drying levels for each separation layer, reducing over-drying and enhancing print quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the one shot color process is used with multiple separation layers on a heatable transfer element, then productivity is improved by transferring all layers simultaneously, but the first separation layer undergoes over-drying due to prolonged exposure, worsening transferability and adhesion
Solution Approach 1:
The patent segments the transfer process by introducing a compressive element that selectively compresses only the first separation layer, differentiating its treatment from subsequent layers. This allows the first layer to retain more carrier liquid while subsequent layers are compressed and dried, resolving the over-drying issue while maintaining simultaneous transfer capability
Solution Approach 2:
The compressive element applies localized compression force to specific regions of the transfer element where the first separation layer is present. This creates different drying conditions for different layers: the first layer remains moist for better adhesion, while subsequent layers are compressed and dried, achieving optimal transferability for each layer type
2Reliability
If the compressive element is engaged to remove carrier liquid from subsequent layers, then transferability of subsequent layers is improved, but the first layer may become overly compressed and lose adequate carrier liquid
Solution Approach 1:
The compressive element is engaged in advance during the transfer process, before the layers are fully deposited on the substrate. This preliminary compression allows carrier liquid to be removed from subsequent layers while the first layer is protected, ensuring optimal conditions for adhesion before the layers are permanently fixed to the substrate
Solution Approach 2:
The compressive element is made dynamically controllable, allowing the system to adjust the timing and duration of compression based on which layers are present on the transfer element. This dynamic control ensures that compression is applied at the optimal moment to remove excess carrier liquid without over-compressing layers that require moisture for adhesion
3Productivity
If air supply is increased to dry subsequent layers faster, then productivity is improved, but the first layer becomes over-dried, worsening adhesion to substrate
Solution Approach 1:
The air supply system is configured to provide localized airflow to different regions of the transfer element. Different air supply levels are applied to different layers: subsequent layers receive higher airflow for faster drying, while the first layer receives reduced or no airflow to maintain adequate moisture for adhesion, achieving both productivity and reliability
Solution Approach 2:
The air supply is segmented into different zones corresponding to different separation layers on the transfer element. This segmentation allows independent control of drying conditions for each layer, enabling the system to dry subsequent layers rapidly while protecting the first layer from over-drying, thus resolving the contradiction between productivity and adhesion quality
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 reduces over-drying of the first layer, improves transferability, and expands the media gamut by maintaining adequate carrier liquid in the first layer and minimizing its presence in subsequent layers, thereby enhancing the overall print quality.
Implementation Method 1
A compressive element is selectively engaged to remove a portion of carrier liquid from subsequent layers
Implementation Method 2
a heatable transfer element, sometimes referred to as an intermediate transfer member, receives the inked image from the imaging element and transfers the inked image to a print substrate
Implementation Method 3
The ink particles are charged and may be arranged upon the imaging element based on a charge pattern of a latent image
Data Source
AI summary
In certain examples, a liquid electrophotographic printer has a compressive element. The compressive element removes a portion of carrier liquid from an inked image on an imaging element. The compressive element is selectively engageable and a controller disengages the compressive element for a first layer of liquid toner so as to retain carrier liquid in the first layer, and engages the compressive element for a subsequent layer of liquid toner so as to remove a portion of carrier liquid from the subsequent layer.