Reflex Printing Registration via Tension Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multicolor printing systems face misregistration errors due to stretch or deformation of the image receiving surface, which conventional reflex printing techniques fail to accurately compensate for, especially when using velocity measurements from compliant drive rolls, leading to reduced image quality.
Innovation Solution
An imaging system with a first measuring device for velocity measurement and a second measuring device for tension measurement, positioned at different locations along the image receiving surface, communicates with a control system to adjust the actuation time of marking stations based on both speed and tension data, using a servo motor to control speed and maintain accurate registration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reflex printing uses velocity measurement from compliant drive rolls, then the system can compensate for speed variations, but measurement accuracy deteriorates leading to misregistration errors
Solution Approach 1:
The patent introduces an intermediary measurement approach by measuring tension in the image receiving surface rather than directly measuring velocity from compliant drive rolls. This tension measurement serves as a mediator that indirectly provides information about speed variations and stretch, avoiding the inaccuracy of direct velocity measurement from compliant rollers while still enabling compensation for speed variations.
Solution Approach 2:
The patent replaces the mechanical velocity measurement system (encoders on compliant drive rolls) with a tension measurement system. By measuring tension in the image receiving surface and using it to calculate position and speed compensation, the system substitutes an inaccurate mechanical measurement approach with a more reliable tension-based measurement approach.
2Manufacturing precision
If double reflex printing measures velocity at two locations, then tension variation compensation is achieved, but device complexity and cost increase
Solution Approach 1:
The patent makes the tension measurement device serve multiple functions: it measures tension in the image receiving surface, which provides information about both speed variations and stretch. This single tension measurement replaces the need for multiple velocity measurement devices, achieving tension variation compensation while reducing device complexity.
Solution Approach 2:
The patent changes the measurement parameter from velocity (which is inaccurate on compliant rolls) to tension (which can be accurately measured). By measuring tension and deriving speed and position information from it, the system achieves accurate color registration without requiring multiple velocity measurement devices.
3Adaptability or versatility
If the image receiving surface is stretchable, then flexibility is improved, but registration accuracy deteriorates due to deformation
Solution Approach 1:
The patent implements feedback by continuously measuring tension in the image receiving surface and using this information to adjust marking station actuation timing. The tension measurement provides real-time feedback about stretch and speed variations, allowing the system to compensate for deformation and maintain registration accuracy on flexible media.
Solution Approach 2:
The patent performs preliminary action by measuring tension upstream and calculating the expected stretch and position adjustments before the image receiving surface reaches the marking stations. This allows the system to pre-compensate for deformation effects, ensuring accurate registration even when using stretchable media.
Data Source
AI summary
The present disclosure provides for an imaging system comprising an image receiving surface which is moved in a downstream direction; a first marking station which applies a first image to the image receiving surface; and, a second marking station, downstream of the first marking station, which applies a second image to the image receiving surface. The imaging system further comprises a first measuring device at a first location at a beginning of a platen which outputs velocity measurement information related to the moving image receiving surface; a second measuring device at a second location at an end of the platen which outputs tension measurement information related to a tension increase in the media receiving surface between the first and second locations; and, a control system in communication with the first and second marking stations, the control system being configured for determining a modified actuation time of at least one of the first and second marking stations based on the information provided by the first and second measuring devices.