Photosensitive Drum Speed Variation for Color Registration
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Solution Overview
Problem
Existing image forming apparatuses face challenges in achieving precise color registration, particularly in compensating position differences between photosensitive drums, which can result in errors greater than one pixel when only adjusting the time point of exposure or motor speed.
Innovation Solution
The apparatus employs a processor to calculate offset values for each color and control the time point of exposure and driving speed of photosensitive drums, allowing for precise adjustment of the transcription position by compensating for offset differences through a combination of exposure timing and motor speed adjustments, even during non-exposure or non-transcription sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If only the time point of exposure is adjusted, then color registration is improved, but position differences greater than one pixel cannot be compensated
Solution Approach 1:
The patent combines two adjustment methods (exposure timing adjustment and motor speed adjustment) into a unified color registration system. The exposure timing adjustment handles position differences of one pixel or less, while the motor speed adjustment handles larger position differences, together achieving comprehensive compensation that neither method could achieve alone.
2Manufacturing precision
If motor speed is adjusted to compensate position differences, then transcription position is improved, but position differences greater than one pixel still cannot be fully compensated
Solution Approach 1:
The patent segments the color registration adjustment into two distinct components: exposure timing adjustment for fine-tuning (one pixel or less) and motor speed adjustment for coarse-tuning (larger position differences). This segmentation allows each component to specialize in its optimal range, achieving overall high precision.
3Measurement precision
If adjustment is performed during non-exposure or non-transcription sections, then color registration is improved, but additional time is required
Solution Approach 1:
The patent performs color registration adjustments during non-exposure or non-transcription sections, preparing the system in advance for the actual printing operation. This preliminary action ensures that when printing begins, the color registration is already optimized, preventing rework and time loss during production.
4Manufacturing precision
If all four photosensitive drums are independently controlled, then color registration precision is improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic control of all four photosensitive drums, allowing each drum's motor speed and exposure timing to be independently adjusted based on detected position differences. This dynamic control enables precise compensation for each color channel while the processor coordinates the adjustments to manage system complexity.
Data Source
AI summary
An example image forming apparatus includes a printing engine including a plurality of photosensitive drums, a motor device to provide a driving force to each of the plurality of photosensitive drums, and a processor to control the printing engine such that printing data is printed on a printing paper and control the motor device such that at least one of the plurality of photosensitive drums operates at a different speed from the other photosensitive drums while the printing data is printed.