Digital Printing Press Development Unit Ink Control
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Solution Overview
Problem
Digital printing presses face issues with image quality degradation due to unwanted ink transfer in non-image areas, leading to a doubling of background ink in overlap regions, particularly noticeable with inks like white or silver, resulting in unacceptable image quality.
Innovation Solution
The development unit is arranged to change between states based on whether an image or non-image portion of the photo imaging member is presented, preventing ink transfer to non-image areas by adjusting voltages and positions, thereby reducing background ink in overlap regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the photo imaging member is rotated and development units apply ink during each rotation, then continuous image production is achieved, but background ink accumulates in overlap regions causing image quality degradation
Solution Approach 1:
The photo imaging member surface is segmented into image-bearing areas and non-image-bearing areas. The development units are controlled to apply ink only to image-bearing areas by selectively discharging or not discharging ink during different phases of the rotation cycle, preventing background ink accumulation in overlap regions while maintaining continuous production capability
Solution Approach 2:
The development units operate in a periodic manner synchronized with the rotation of the photo imaging member. Ink application is activated only during specific angular positions when image-bearing areas are presented to the development units, and deactivated during other positions to prevent background ink transfer, thereby resolving the contradiction between continuous production and image quality
2Productivity
If development units are positioned close to the photo imaging member surface for precise ink application, then ink transfer efficiency is improved, but unwanted ink transfer to non-image areas increases
Solution Approach 1:
The development units are designed with dynamic positioning capability, allowing them to move between a working position (close to the photo imaging member surface for efficient ink transfer) and a retracted position (away from the surface to prevent unwanted ink transfer). This dynamic adjustment enables the system to optimize ink transfer efficiency when needed while preventing background ink accumulation at other times
Solution Approach 2:
The system incorporates control mechanisms that monitor the position of the photo imaging member and the state of image-bearing areas, providing feedback to the development units. Based on this feedback, the development units adjust their ink application activity and positioning in real-time, ensuring efficient ink transfer to image areas while preventing unwanted transfer to non-image areas
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 significantly improves image quality by reducing unwanted ink transfer to non-image areas, minimizing background ink in overlap regions and maintaining image continuity without the need for structural modifications.
Implementation Method 1
preventing ink transfer to non-image areas by adjusting voltages
Data Source
AI summary
A developing section for a digital printing press includes a controller to control a development unit such that a configuration of the development unit is to be in a first state or a second state based on a determination by the controller comparing a location of a portion of the surface of a photo imaging member presented to the development unit with a location of a transition between an image portion and a portion of the surface of the photo imaging member not in the image portion.