Focal Point Positioning via Edge Detection in Image Forming Apparatus
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately determining the positional relationship between the focal point of the exposing means and the photosensitive body, leading to issues like isolated dot disappearance and increased density in halftone portions, which requires expensive density sensors and limits accuracy.
Innovation Solution
An image forming apparatus equipped with a mark forming unit, a light sensor, an edge detector, and a deciding unit that uses edge detection to determine the positional relation between the focal point and the photosensitive body, eliminating the need for expensive density sensors and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a density sensor is used to measure the density of a halftone mark to determine the positional relation between the focal point and photosensitive body, then the measurement precision is improved, but the device complexity and cost increase
Solution Approach 1:
The patent replaces the expensive density sensor with a simple light sensor that detects the presence and position of the mark. The light sensor uses basic optical detection principles rather than requiring complex density measurement capabilities, thereby reducing device complexity and cost while maintaining sufficient measurement precision for determining focal point position.
Solution Approach 2:
The patent substitutes the mechanical/optical density measurement system with a simpler light detection system. Instead of using a density sensor that requires complex optical path control and density calculation, the invention uses a light sensor to detect light transmission through the mark, converting a complex measurement problem into a simpler binary detection problem.
2Measurement precision
If a density sensor is used to sense the density of a halftone mark, then the measurement precision is improved, but the loss of energy increases due to expensive components and limited accuracy improvement
Solution Approach 1:
The patent employs a low-cost light sensor that consumes minimal energy compared to a density sensor. The light sensor simply detects light transmission through the mark without requiring the complex power consumption associated with density sensor operations, thereby reducing energy loss while achieving sufficient measurement precision for the application.
3Device complexity
If the light from the exposing means is not focused on the photosensitive body, then the device complexity is reduced, but the manufacturing precision deteriorates causing isolated dot disappearance and increased halftone density
Solution Approach 1:
The patent performs a preliminary detection of the mark position and focal point alignment before actual image formation. By detecting the mark with the light sensor and determining whether the light is properly focused, the system can correct alignment issues in advance, ensuring manufacturing precision is maintained without increasing device complexity during the actual imaging process.
Solution Approach 2:
The patent implements a feedback mechanism where the light sensor detects the mark position and provides information about focal point alignment. This feedback allows the system to adjust or correct the focusing condition before image formation, thereby maintaining manufacturing precision while keeping the device complexity low during normal operation.
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 solution allows for precise determination of the focal point position without the need for expensive density sensors, enhancing the accuracy of image formation and preventing issues like isolated dot disappearance and increased halftone density.
Implementation Method 1
a light sensor which senses light reflected by the carrier body
Data Source
AI summary
An image forming apparatus, having an exposing unit for exposing a photosensitive body to form a_latent image, a developing unit for forming a developer image corresponding to the latent image, a carrier body moved through a portion opposite to the photosensitive body onto which the developer image formed on the photosensitive body is transferred, a mark forming unit for controlling the exposing unit to form a mark on a surface of the carrier body, a light sensor for sensing light reflected by the carrier body, an edge detector for sensing an edge of the mark on the carrier body based on an_output of the light sensor and a deciding unit for deciding a positional relation between a focal point of the exposing unit and the surface of the photosensitive body based on the edge detected by the edge detector.