Gravity-Assisted Sheet Registration in Printers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current sheet transport systems face challenges in accurately registering large or heavy sheets at high speeds due to increased stresses and limitations in correction time, leading to potential sheet damage or misregistration, especially when trying to handle larger sheet sizes and faster speeds.
Innovation Solution
A gravity-assisted wall registration system that includes a transport member angled in the cross-process direction, with a registration wall and driven rotation mechanisms allowing sheets to slide under gravity for alignment, reducing skew and lateral shifts without the need for complex steering algorithms or feedback systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If registration correction algorithms are used to steer sheets at high speeds, then printer speed is improved, but sheet trailing edges are driven into sidewalls causing damage or jams
Solution Approach 1:
The registration system segments the correction process into two independent components: skew correction handled by the translating carriage and lateral correction handled by the rotation mechanisms. This segmentation allows each component to operate within its optimal performance range, preventing the harmful fishtailing effect that occurs when both corrections are applied simultaneously through a single mechanism.
Solution Approach 2:
The patent introduces a second degree of freedom by adding rotation mechanisms that operate in the lateral dimension, independent of the skew correction carriage operating in the process direction. This dimensional separation allows sheets to be registered without inducing the tail-wag motion that causes trailing edges to contact sidewalls.
2Ease of operation
If independent drive rolls are used for skew correction with translating carriage for lateral correction, then decoupling of corrections is achieved, but maximum printer speed is limited by carriage return time
Solution Approach 1:
The rotation mechanisms are designed to be self-contained and independently controllable, eliminating the need for the heavy translating carriage to perform lateral corrections. Each rotation mechanism can independently adjust lateral position without waiting for carriage return, allowing continuous high-speed operation while maintaining the benefits of decoupled correction.
3Measurement precision
If manual alignment procedures are performed on preceding modules, then mean input error is reduced, but sheet-to-sheet variations still result in misregistration
Solution Approach 1:
The system incorporates sensors that detect the actual position and orientation of each sheet as it enters the marking module. This real-time feedback information is used to dynamically adjust the rotation mechanisms and translating carriage, enabling correction of both mean errors and sheet-to-sheet variations, ensuring accurate registration for every individual sheet.
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 solution effectively reduces gross misalignment and allows for the registration of larger, heavier sheets at higher speeds by utilizing the weight of the media for alignment, eliminating the need for fishtailing maneuvers and enhancing the overall registration accuracy and reliability.
Implementation Method 1
A gravity-assisted wall registration system includes a transport member including a surface on which an associated sheet is translated in a process direction. The surface defines an angle with respect to horizontal in a cross-process direction of at least one degree.
Implementation Method 2
Each drive member includes a sliding mechanism, at a periphery of the drive member, which enables the sheet to slide, under gravity, on the surface, toward the registration wall into an alignment position, in contact with the registration wall.
Data Source
AI summary
A gravity-assisted registration system suited to use in a printing device includes a transport member with a surface on which an associated sheet is translated in a process direction. The surface defines an angle with respect to horizontal in a cross-process direction. A registration wall, adjacent a lower end of the surface, defines a registration edge for registering the sheet. A drive mechanism drives at least one rotation mechanism, for translating sheet in the process direction, each rotation mechanism including at least one drive member with an axis of rotation parallel to the surface in the cross-process direction, Each drive member includes a sliding mechanism, at a periphery of the drive member, enabling the sheet to slide, under gravity, on the surface, toward the registration wall into an alignment position, in contact with the registration wall.