Staged LED Exposure Array Layout for Inrush Current and Step Control
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Solution Overview
Problem
Existing image forming devices using linear light sources with arrayed light-emitting elements face issues of increased inrush current and image quality deterioration due to phase differences between light-emitting element groups, leading to step generation.
Innovation Solution
The exposure device employs a panel member with light-emitting elements arranged in stages, using signal output units to provide phase-differentiated drive signals and adjust the distance between element arrays based on a phase correction value, ensuring synchronized light emission to prevent step generation and manage inrush current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple light-emitting elements are arrayed in main scanning and sub-scanning directions to increase pixel density, then exposure amount increases, but inrush current to drive circuit increases
Solution Approach 1:
The light-emitting element array is divided into multiple element arrays arranged in stages along the sub-scanning direction. Each element array is driven independently with phase-differentiated signals, segmenting the total current load across time and space to reduce peak inrush current while maintaining high pixel density
2Power
If phase-differentiated drive signals are applied to light-emitting element groups, then inrush current is reduced, but steps are generated between element groups in sub-scanning direction
Solution Approach 1:
The physical distance between element arrays in the sub-scanning direction is adjusted based on phase correction values that compensate for the temporal phase differences in drive signals. By changing the spatial parameter (distance) to match the temporal parameter (phase difference), the invention eliminates step generation while maintaining current reduction benefits
Solution Approach 2:
Phase correction values are calculated and applied to adjust the distances between element arrays, creating a feedback mechanism that compensates for phase differences. This ensures that light emission from different element arrays aligns properly on the photoreceptor surface, preventing image degradation
3Power
If light-emitting elements are arranged in multiple stages in sub-scanning direction, then inrush current is suppressed, but distance between element arrays must be precisely controlled
Solution Approach 1:
The distances between element arrays are pre-calculated and set based on phase correction values before operation. This preliminary positioning eliminates the need for real-time adjustment during operation, simplifying the control system while achieving precise alignment compensation
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 approach maintains image quality by preventing step formation while optimizing exposure amount and reducing inrush current, allowing for precise image formation without quality degradation.
Implementation Method 1
a driver causing each of the plurality of light-emitting elements to emit light individually, based on the drive signals
Implementation Method 2
an electrophotographic image forming device is widely used in which an electrostatic latent image is formed on a photoreceptor using a laser beam or the like
Data Source
AI summary
An image forming device includes a panel member that faces a photoreceptor and includes a plurality of light-emitting elements. An exposure device includes a signal output unit that outputs drive signals having different phases, and a driver that causes each of the plurality of light-emitting elements to emit light individually, based on the drive signals. In the panel member, element arrays including the plurality of light-emitting elements arranged in a main scanning direction are arranged in a plurality of stages arranged in a sub-scanning direction. The signal output unit outputs the drive signals having a phase difference to the element arrays, respectively. A distance in the sub-scanning direction between the element arrays adjacent to each other is set based on a phase correction value obtained by multiplying a circumferential speed of the front surface of the photoreceptor by the phase difference.