Optical Scanning Apparatus Phase Control for Polygon Mirrors
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Solution Overview
Problem
Existing optical scanning apparatuses with multiple polygon mirrors require long times for phase control, leading to extended First Page Out Time (FPOT) in image forming apparatuses due to independent phase control of each mirror using a common phase reference signal.
Innovation Solution
An optical scanning apparatus with detection units and phase control units for each polygon mirror, where the phase control of one mirror is used as a reference to shorten the phase control time of other mirrors, allowing for simultaneous phase control based on detection signals and target phases set relative to each other.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If independent phase control is performed for each polygon mirror using a common phase reference signal, then each polygon mirror can be controlled independently, but the phase control time becomes long and FPOT is extended
Solution Approach 1:
The patent applies preliminary action by pre-setting target phases for each polygon mirror based on their respective image carriers and light beam paths. Instead of performing phase control from scratch for each mirror, the system pre-calculates and sets appropriate target phases, allowing the phase control to converge faster to the desired state, thereby reducing overall phase control time while maintaining independent control capability
Solution Approach 2:
The patent segments the phase control process by providing separate phase control circuits for each polygon mirror rather than using a single centralized control. Each phase control circuit independently manages its assigned polygon mirror with dedicated target phase settings, enabling parallel processing of phase control operations across multiple mirrors, which significantly reduces total phase control time compared to sequential independent control
2Manufacturing precision
If multiple polygon mirrors are controlled sequentially with independent phase control, then each mirror receives proper phase adjustment, but the First Page Out Time (FPOT) is extended
Solution Approach 1:
The system performs preliminary action by pre-setting target phases for each polygon mirror based on their specific optical paths and image carrier positions. This preconfiguration allows the phase control to start from a more favorable initial state, reducing the time required to achieve accurate phase alignment while maintaining the precision needed for proper image formation, thus improving FPOT without sacrificing phase accuracy
Solution Approach 2:
The patent implements segmentation by dividing the phase control system into multiple independent phase control circuits, each dedicated to a specific polygon mirror. This segmentation enables simultaneous or near-simultaneous phase control of multiple mirrors rather than strict sequential control, maintaining phase accuracy for each mirror while significantly reducing the overall time to achieve synchronized operation across all mirrors, thereby improving productivity and reducing FPOT
Data Source
AI summary
An optical scanning apparatus includes a first rotating polygonal mirror that deflects a light beam such that the light beam scans a surface of a first image carrier, and a second rotating polygonal mirror that deflects a light beam such that the light beam scans a surface of a second image carrier. The optical scanning apparatus further includes a first phase control unit that performs phase control of the first rotating polygonal mirror based on a first detection signal output from a first detection unit and a first target phase, and a second phase control unit that performs phase control of the second rotating polygonal mirror based on a second detection signal output from a second detection unit and a second target phase, which is set with respect to the first target phase.