Toner Density Detection Using Normal and Diffused Reflection
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Solution Overview
Problem
Existing image forming apparatuses face challenges in maintaining image quality stability due to variations in density across the main scanning direction, leading to increased costs from the need for multiple sensors to form and detect multiple test images for precise density correction.
Innovation Solution
A configuration using a rotary member with multiple detection images formed on it, where a first detecting unit with a singular light-receiving element for normal reflection and a second detecting unit with a singular light-receiving element for diffused reflection are employed, along with a control unit to obtain toner density values from both detection results, reducing the need for multiple sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are used to form and detect multiple test images at different positions in the main scanning direction, then the precision of density correction control is improved, but the cost increases
Solution Approach 1:
The patent combines multiple detection functions into a single sensor by forming multiple test images with different spatial frequencies on a single rotary member. The single sensor detects all test images sequentially as the rotary member rotates, merging the functionality of what would traditionally require multiple sensors into one detection device.
Solution Approach 2:
The patent uses periodic rotation of the rotary member to bring different test images into the detection position sequentially. By forming test images at different angular positions on the rotary member and rotating it periodically, the system achieves multiple measurements over time using a single sensor, eliminating the need for multiple simultaneous sensors.
2Measurement precision
If multiple test images are formed to account for density variance in the main scanning direction, then the accuracy of density measurement is improved, but the number of detecting devices increases
Solution Approach 1:
The patent adds the temporal dimension to the measurement process by using a rotating rotary member. Instead of having multiple sensors detect test images simultaneously at different positions, a single sensor detects multiple test images sequentially over time as they rotate into position, converting a spatial measurement problem into a temporal measurement process.
Solution Approach 2:
The rotary member serves multiple functions: it acts as both the carrier for multiple test images and the mechanism that brings them sequentially to the detection position. The rotation of the rotary member automatically sequences the detection of different test images without requiring additional actuation mechanisms.
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 enhances the precision of density correction control while minimizing cost by using fewer sensors, effectively addressing the variance in image density across the scanning direction.
Implementation Method 1
a first detecting unit having a singular first light-receiving element disposed to face a direction of normal reflection of light, the light having been emitted from a first light-emitting element toward a first detection image formed on the rotary member and reflected thereat
Data Source
AI summary
Provided are a first detecting unit having a singular first light-receiving element disposed to face a direction of normal reflection of light, the light having been emitted from a first light-emitting element toward a first detection image formed on the rotary member and reflected thereat, and a second detecting unit having a singular second light-receiving element disposed to face a direction different from a direction of normal reflection of light, the light having been emitted from a second light-emitting element toward a second detection image formed on the rotary member and reflected thereat. A value relating to toner density is obtained based on a first detection result detected by the first detecting unit and a second detection result detected by the second detecting unit.