Skew Compensation in Multi-Beam Laser Scanning Systems
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Solution Overview
Problem
Current deskewing methods for multi-beam laser scanning systems are inadequate, leading to print location errors and visual artifacts due to manufacturing errors and variable driver board delays, requiring either theoretical calculations that fail to account for optical magnification and driver board delays or costly laboratory calibrations that are not practical for frequent adjustments.
Innovation Solution
A skew compensation apparatus and method using a delay commencement detector and position detector to automatically adjust beam delays, ensuring accurate beam positioning by detecting skew and iteratively converging on a compensation solution, allowing for real-time calibration and addressing component drift over the printer's lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If theoretical calculation methods are used for deskewing, then the process is simple and fast, but it fails to account for optical magnification and driver board delays resulting in inaccurate compensation
Solution Approach 1:
The patent implements feedback by using position detectors to measure actual beam positions and comparing them against expected positions. The detected position information is fed back to the controller, which then adjusts the delay values for each beam to achieve accurate positioning. This closed-loop feedback mechanism resolves the contradiction by providing both speed (through automated measurement) and precision (through iterative adjustment based on actual measurements).
Solution Approach 2:
The patent replaces manual mechanical adjustment methods with automated electronic detection and control systems. Position detectors electronically measure beam positions, and the controller automatically calculates and applies delay corrections, eliminating the need for manual calibration procedures while achieving higher precision through computational methods that account for optical magnification and driver board delays.
2Measurement precision
If laboratory calibration is performed to achieve accurate beam positioning, then measurement precision is improved, but the process becomes costly and impractical for frequent adjustments
Solution Approach 1:
The patent implements self-service calibration by incorporating position detectors and control electronics directly into the laser scanning system. The system automatically measures its own beam positions and adjusts its own timing without requiring external laboratory equipment or personnel. This integrated self-calibration capability provides accurate positioning while eliminating the complexity and cost of external laboratory calibration processes.
Solution Approach 2:
The patent makes the calibration system universal by designing it to be self-contained and reusable within the printing system. The position detectors and controller work together to provide ongoing calibration capabilities that can be performed frequently without requiring specialized laboratory facilities, making the system adaptable to various operating conditions and maintenance needs.
3Manufacturing precision
If laser sources are built with larger spacings between individual beams, then manufacturing precision is improved, but the inter-beam spacing becomes a large percentage error requiring skew correction
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the timing parameters (delay values) for each beam based on actual measured positions. Instead of relying on fixed manufacturing tolerances, the system changes the operational parameters through computational adjustment, allowing the same physical laser source to achieve accurate positioning across different operating conditions without requiring complex mechanical adjustments.
4Ease of operation
If driver board delays are not compensated for, then the system is simpler to operate, but print location errors and visual artifacts occur
Solution Approach 1:
The patent uses feedback from position detectors to automatically measure and compensate for driver board delays. The system measures actual beam positions, compares them against expected positions, and adjusts timing parameters accordingly. This automated feedback mechanism handles the complexity of delay compensation internally, maintaining ease of operation while achieving high print location accuracy through computational correction rather than manual adjustment.
Data Source
AI summary
Skew compensation apparatus for compensating for skew of a multi-beam scanning source, comprises: delay commencement detector(s) for detecting the start of a beam scanner position, position detectors for detecting the position of the multiple beams at a predefined interval following the commencement, so that the position indicates skew of the respective beam, and compensating electronics for automatically inserting a compensation for the skew by altering a delay into a timing signal for switching the respective beam. The commencement detector can be an existing start of scan detector and the apparatus can be built into the writing head, particularly at the conjugate location to the focal plane or at the focal plane of a laser printer or the like to provide a self-calibrating printer.