Sensor Tilt Angle Determination Using Optical Time Difference
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately determining the installation angle of sensors relative to the image bearing surface, as this angle must be precisely aligned with a reference angle for accurate positional and density corrections, but visual determination is not feasible, leading to potential errors in tilt correction.
Innovation Solution
The apparatus includes a photosensor with a light emitting element and two light receiving elements, which generates detected information based on light reflected from specific regions on the image bearing surface, allowing for the calculation of time difference information. This information is used to determine the tilt between the sensor's installation angle and the reference angle, facilitating easy adjustment by referencing pre-stored tilt information tables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor installation angle is not precisely aligned with the reference angle, then adjustment operation is required, but visual determination of the angle is not feasible leading to potential errors
Solution Approach 1:
The patent replaces visual/mechanical angle determination with an optical measurement system. A light emitting element projects light to the image bearing surface, and light receiving elements detect the reflected light. The sensor unit measures the time difference for light to travel to and from different detection regions, substituting mechanical angle measurement with optical time-of-flight measurement to achieve precise angle detection without visual feasibility constraints.
Solution Approach 2:
The patent introduces light as an intermediary to measure the sensor installation angle. Instead of directly measuring the angle between the sensor and image bearing surface, the system uses light travel time as a mediator. The light emitting element sends light to the image bearing surface, and the light receiving elements detect the reflected light, with the control unit calculating the angle based on time difference information from the light path.
2Ease of operation
If the sensor installation angle is different from the reference angle, then adjustment operation is required, but the adjustment process is complex and time-consuming
Solution Approach 1:
The patent enables the sensor unit to automatically determine its own installation angle without requiring external adjustment tools or complex procedures. The sensor unit itself, with its light emitting element and light receiving elements, performs the measurement and provides time difference information that the control unit uses to calculate the installation angle, making the adjustment process self-service and simplifying the operation.
Solution Approach 2:
The patent changes the measurement parameter from visual angle estimation to quantitative time difference measurement. By measuring the time difference for light to travel to and from different detection regions, the system converts a qualitative visual adjustment task into a quantitative measurement that can be precisely calculated and used for accurate angle determination.
3Manufacturing precision
If visual determination of sensor angle is used, then the process is simple, but the accuracy of positional and density corrections deteriorates
Solution Approach 1:
The patent segments the light detection function into multiple light receiving elements (first light receiving element and second light receiving element), each detecting light from different detection regions (first detection region and second detection region). This segmentation allows the system to measure time differences for different light paths, providing multiple data points for accurate angle calculation while maintaining a relatively simple overall structure.
Solution Approach 2:
The sensor unit serves multiple functions: it forms images on the image bearing surface, detects the formed images, and simultaneously measures the installation angle through its light emitting and light receiving elements. This multi-functionality reduces the need for separate angle measurement devices, maintaining device simplicity while achieving high measurement precision for accurate positional and density corrections.
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 method enables accurate detection and adjustment of the sensor's angle, ensuring precise positional and density corrections during image formation, thereby improving the overall accuracy and efficiency of the image forming process.
Implementation Method 1
The light emitting element emits detected light to the image bearing surface
Implementation Method 2
The first light receiving element receives a first part of the detected light that is reflected from the first detection region
Implementation Method 3
The circuitry generates, when the specific image on the image bearing surface moves, time difference information according to a difference between a first time point and a second time point
Data Source
AI summary
An image forming apparatus includes an image forming device forming an image, a transfer belt having an image bearing surface on which the image moves to first and second regions, a sensor installed at an installation angle to the image bearing surface and including a light emitting element emitting light, a first and second light receiving elements receiving light reflected from the first and second regions, respectively, circuitry to generate first and second information according to light entered the first and second light receiving elements, respectively, generate, when the image moves, time information according to a difference between first and second times at each of which the first and second information, respectively, reach a threshold, obtain a tilt table based on the time difference information, and determine, by the tilt table, tilt information corresponding to the time information and indicating a difference between the installation angle and a reference angle.