Image Sensor Resin Layer for Leaking Light Control
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Solution Overview
Problem
Image density sensors in electrophotographic apparatuses face challenges in accurately detecting image density due to individual differences and variations in sensitivity characteristics caused by leaking light, which are exacerbated by adjustments in driving current and output gain, leading to inconsistent image quality.
Innovation Solution
An image forming apparatus is designed with a sensor configuration that includes a substrate-mounted light-emitting and light-receiving elements, along with a blocking member to minimize leaking light, and a control unit that adjusts the driving current and output gain to maintain consistent detection values, using a memory to store data for optimal measurement conditions based on reference member reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If surface-mounted light-emitting element and light-receiving element are directly mounted on substrate, then device size is reduced and manufacturing cost is lowered, but leaking light occurs causing individual differences in sensitivity characteristics
Solution Approach 1:
A resin layer is introduced as an intermediary medium between the light-emitting element and light-receiving element. This resin layer has light-transmitting properties that allow controlled light propagation while preventing direct light leakage between the elements, thereby reducing individual differences in sensitivity characteristics while maintaining the surface-mounted configuration
Solution Approach 2:
The patent uses a simple resin coating method instead of complex precision positioning structures. The resin layer is applied directly to the substrate surface, providing an effective solution to the leaking light problem without requiring expensive precision manufacturing processes
2Measurement precision
If driving current of light-emitting element is increased to compensate for toner stain, then detection accuracy is improved, but amount of leaking light increases causing sensitivity characteristic changes
Solution Approach 1:
The resin layer acts as a light-guiding intermediary that channels light from the light-emitting element through the substrate to the light-receiving element, reducing the impact of toner stain on the detection path while controlling light propagation to minimize leaking light effects even at higher driving currents
3Measurement precision
If output gain of light-receiving element is increased to reduce toner stain influence, then detection accuracy is improved, but leaking light influence increases causing individual differences
Solution Approach 1:
The resin layer provides a consistent optical path between the light-emitting element and light-receiving element, reducing the influence of leaking light on the detection signal. This allows output gain to be increased for better toner stain compensation while maintaining consistent detection values across different sensors
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 configuration reduces individual differences in sensitivity characteristics and maintains accurate image density detection, ensuring consistent image quality by compensating for leaking light and toner stain effects, thereby improving the reliability of image density correction.
Implementation Method 1
a light-emitting element and a light-receiving element which are directly mounted on a surface of a substrate
Implementation Method 2
light emitted from the light-emitting element propagates on the surface of the substrate, enters an inner layer of the substrate, and easily reaches the light-receiving element
Implementation Method 3
a sensor including a substrate, a light-emitting element provided on the substrate, a light-receiving element provided on the substrate
Data Source
AI summary
An image forming apparatus includes an image forming unit configured to form an image, a reference member, a sensor including a substrate, a light-emitting element provided on the substrate, a light-receiving element provided on the substrate, and a blocking member provided between the light-emitting element and the light-receiving element on the substrate, the sensor configured to output an output value based on a light reception result of the light-receiving element, a memory storing data related to a relationship between a measurement condition and an offset value, and a controller configured to control the sensor based on a plurality of measurement conditions to acquire an output value corresponding to a measurement result of reflected light from the reference member, and determine a measurement condition for measuring the image based on the acquired output value and the data stored in the memory.