Pixilated Photoconductor for High Viscosity Ink Printing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrophotographic printing systems are limited by the use of low viscosity inks, restricting the range of printable materials and substrates, and requiring separate photoreceptors and cleaning processes for each printing pass, which hinders the use of higher viscosity inks and variable data printing.
Innovation Solution
A hybrid system combining electrophotography and gravure printing using a pixilated photoreceptor with electrically isolated cells that can hold and charge liquid surface application materials, allowing for image-wise charging and discharge to transfer higher viscosity inks onto a substrate with reduced cleaning requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional electrophotographic printing systems are used, then low viscosity inks can be printed, but the range of printable materials and substrates is restricted and cleaning is required for every printing pass
Solution Approach 1:
The patent combines electrophotography and gravure printing into a hybrid system where the photoreceptor drum also serves as the ink-bearing surface with recessed cells. This merging eliminates the need for separate cleaning processes while enabling high viscosity ink printing, thus resolving the contradiction between versatility and ease of operation.
Solution Approach 2:
The photoreceptor drum is designed to perform multiple functions: it acts as both the electrophotographic imaging surface and the gravure ink-bearing surface with recessed cells. This multi-functionality allows the system to handle various ink viscosities and substrate types without requiring separate cleaning operations, addressing both versatility and operational simplicity.
2Adaptability or versatility
If gravure printing is used, then higher viscosity inks can be accommodated, but the image is not variable from printing to printing
Solution Approach 1:
The hybrid system merges gravure's ink retention cells with electrophotography's variable imaging capability. The photoreceptor drum maintains recessed cells for ink holding like gravure, but uses electrostatic charging and light exposure to create variable images, thus achieving both high viscosity ink accommodation and variable data printing.
Solution Approach 2:
The system uses dynamic electrostatic charging and discharging of the photoreceptor surface to control ink transfer. By varying the charge distribution through light exposure patterns, the system can dynamically adjust the printed image while maintaining the gravure cell structure for ink retention, enabling variable data printing with high viscosity inks.
3Productivity
If ink viscosity is reduced for electrophotographic printing, then printing throughput is improved, but the variety of usable inks and substrates is limited
Solution Approach 1:
The hybrid system combines the rapid ink transfer mechanism of electrophotography with the ink retention capability of gravure cells. This allows higher viscosity inks to be used without sacrificing throughput, as the electrostatic field efficiently transfers the thicker ink from the cells to the substrate, resolving the contradiction between productivity and material versatility.
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
Enables variable data printing with a wide range of surface application materials, including high viscosity inks, on various substrates, reducing ink spreading and dot gain, and eliminating the need for separate photoreceptors and extensive cleaning, thus expanding printing capabilities and efficiency.
Implementation Method 1
a charged receptor surface is exposed to an image to be printed. The charge on the receptor surface is modified (e.g., discharged) where it is exposed to the image.
Implementation Method 2
The different charge states (e.g., charged or discharged) are used to selectively retain a charged pigment material (e.g., ink or toner).
Implementation Method 3
An ink is spread over the image carrier such that ink is retained in the cells, but not on the lands between the cells.
Implementation Method 4
The ink wicks out of the cells and onto the substrate, where it is dried, thereby imparting a marking onto the substrate.
Implementation Method 5
In cells adjacent charged lands, the pigment material forms a concave meniscus, and in cells adjacent discharged lands the pigment material forms a convex meniscus, due to the electric field effects on the surface tension of the pigment material.
Data Source
AI summary
A printing sub-system including same including a pixilated photoconductive member (such as a photobelt) is disclosed. Electrically isolated cells hold surface application material above the photoconductor. The surface application material is first charged. Charge on the surface application material in an individual cell may then be discharged by exposure of a region of the photoconductor proximate that cell to light from an optical addressing system. The surface application material is brought into proximity of an image receiving member such as paper, which is either charged or proximate a charge source. Charged surface application material in a cell may then be electrostatically transferred from the cell onto the image receiving member, while discharged surface application material remains in the cell. The subsystem may form a part of a complete printing system using many existing components. Among other advantages, viscous liquid surface application material may thereby be printed.