Optical Writing Device Write Start Position Control
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Solution Overview
Problem
Existing optical writing devices face challenges in maintaining consistent concentration and shape of black pixels in screening patterns due to changes in the write start position, leading to variations in image gradation and quality.
Innovation Solution
An optical writing device that includes a control unit to manage the write start position by assigning pixel values to light-emitting elements based on a screening pattern, ensuring consistent exposure and dot formation across the photoreceptor surface, even when the write start position changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the write start position is changed to maintain image quality over long period, then image stability is improved, but the concentration and shape of screening pattern pixels vary
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing correction data for different write start positions before actual printing occurs. The system determines the appropriate screening pattern in advance based on the detected write start position, ensuring that the correct pattern is applied without real-time adjustments during the printing process.
Solution Approach 2:
The patent changes parameters by adjusting the screening pattern selection based on the write start position. When the write start position shifts, the system selects a different screening pattern from pre-stored options that compensates for the position change, thereby maintaining consistent pixel concentration and shape despite the position variation.
2Adaptability or versatility
If different light-emitting elements are used for the same pixel position after write start position change, then the write start position flexibility is improved, but the perceived image quality varies
Solution Approach 1:
The patent uses copying by creating and storing multiple copies of screening patterns that are variations of the same base pattern, each optimized for specific write start position conditions. When the write start position changes, the system retrieves the appropriate copied pattern that matches the new position, ensuring visual consistency without requiring the same physical light-emitting elements.
3Ease of operation
If screening pattern is shifted to accommodate write start position change, then the write start position adjustment is improved, but the pixel concentration distribution becomes inconsistent
Solution Approach 1:
The system performs preliminary preparation by generating and storing multiple screening patterns in advance, each corresponding to different write start position scenarios. This eliminates the need for real-time pattern generation or shifting operations, as the appropriate pre-prepared pattern is simply selected and applied based on the actual write start position.
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 suppresses variance in the concentration of screening patterns, ensuring consistent image quality and gradation by maintaining the same light-emitting elements for corresponding pixels before and after changes in the write start position, thereby preventing perceived differences in the output image.
Implementation Method 1
Light beams emitted from the light-emitting elements 1 are transmitted through the rod-lens array 910 and are focused on a photoreceptor surface
Implementation Method 2
optical writing device that performs optical writing on a photoreceptor by using a light beam
Data Source
AI summary
An optical writing device driving a light-emitting element array, modulating light according to a screening pattern that expresses a dithered image, and performing optical writing by focusing light emitted from the light-emitting element array through a lens array onto a photoreceptor. The optical writing device includes an acquisition unit that acquires a write start position for writing to the photoreceptor in a main scanning direction and a control unit that performs a control when the write start position corresponds to an i-th light-emitting element from a reference position that corresponds to a first light-emitting element in the main scanning direction, i being a positive integer greater than 1, wherein the control unit supplies pixel values to the i-th light-emitting element onwards, the pixel values being assigned from pixels of the screening pattern from an i-th pixel onwards, from a leading pixel of the screening pattern in the main scanning direction.