Exposure Head Temperature Compensation for Uniform Image Exposure
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Solution Overview
Problem
Existing exposure apparatuses in image forming devices experience unevenness in exposure due to temperature-induced displacement of light emitting elements relative to cylindrical lenses, leading to inconsistent image quality along the length of the exposure head.
Innovation Solution
An exposure apparatus with a temperature-sensing mechanism that adjusts exposure amounts and positions using correction gains stored in a memory, based on detected temperature changes, to maintain consistent exposure across the length of the exposure head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If cylindrical lenses are disposed in a staggered arrangement to improve condensing efficiency uniformity, then condensing efficiency is improved, but exposure unevenness occurs due to positional relationship changes with temperature variations
Solution Approach 1:
The patent implements dynamic correction of exposure amounts based on temperature detection. The exposure amount correction unit adjusts the exposure amounts of light emitting elements in real-time according to the detected temperature, compensating for the positional relationship changes between light emitting elements and cylindrical lenses that occur with thermal expansion.
Solution Approach 2:
The patent employs a feedback mechanism where a temperature detection unit continuously monitors the temperature of the exposure head, and this information is fed back to the exposure amount correction unit, which then adjusts the exposure amounts accordingly to maintain uniform exposure despite temperature-induced positional changes.
2Manufacturing precision
If the substrate expands due to heat, then the light emitting elements displace relative to the rod lens array, but providing a dedicated light receiving element to detect expansion increases device complexity
Solution Approach 1:
The patent uses a temperature detection unit that serves multiple purposes: it detects the temperature of the exposure head, which correlates with substrate expansion, and this same temperature information is used to correct exposure amounts. This multi-functional approach eliminates the need for separate expansion detection mechanisms while maintaining exposure uniformity.
Solution Approach 2:
The patent replaces direct mechanical measurement of substrate expansion with a thermal-based measurement system. Instead of using a dedicated light receiving element to physically detect expansion, the system uses temperature detection to infer expansion and compensates through software-based exposure amount correction.
3Manufacturing precision
If correction is applied based on fixed positional relationships, then exposure uniformity is improved at reference temperature, but temperature changes cause the positional relationship to change and unevenness reoccurs
Solution Approach 1:
The patent transitions from static correction (fixed at reference temperature) to dynamic correction (adaptive to temperature changes). The exposure amount correction unit continuously adjusts correction values based on real-time temperature detection, enabling the system to adapt to varying thermal conditions and maintain exposure uniformity across different temperatures.
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
The solution effectively reduces exposure unevenness by dynamically correcting exposure amounts and positions, ensuring consistent image quality despite temperature fluctuations.
Implementation Method 1
a temperature detection unit that detects a temperature that correlates with a temperature of the exposure head
Implementation Method 2
a condensing optical system arranged along a lengthwise direction of the substrate and configured to condense light output from the plurality of light sources onto a circumferential surface of the photosensitive member
Implementation Method 3
organic electro-luminescence (EL) type exposure devices that use organic EL elements for exposure
Data Source
AI summary
An exposure head includes a substrate on which light sources are mounted, and a condensing optical system. A memory stores a profile indicating correction gains for exposure amounts. A sensor detects a temperature. A processor acquires a correction gain that corresponds to a position of a light source that reached an exposure timing, corrects, for each of the light sources, an exposure amount of the light source with the correction gain corresponding to the position of the light source, and adjusts, for each of the light sources, a reference position of the corresponding correction gain in the profile in accordance with the temperature detected by the sensor.