Developing Unit Positioning for Photoconductive Body Exposure Control
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Solution Overview
Problem
The existing image forming apparatuses face challenges in suppressing unnecessary exposure of the photoconductive body during synchronous detection writing, leading to optical fatigue and ghost image generation due to excessive exposure.
Innovation Solution
The apparatus includes a moving mechanism that positions the developing unit to open and close the optical path, preventing unnecessary exposure by emitting the light beam only after determining the detection signal from the optical sensor, thus controlling the exposure to the photoconductive body effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If synchronous detection writing is performed by exposing the photoconductive body to the laser beam, then the optical detector can detect the laser beam for synchronization, but unnecessary exposure causes optical fatigue and ghost image generation
Solution Approach 1:
The patent divides the photoconductive body into two distinct surfaces: a first surface for receiving the laser beam during synchronous detection, and a second surface for receiving the actual image to be formed. This segmentation allows the detection function and image formation function to be spatially separated, enabling synchronization detection without causing optical fatigue or ghost images on the image-receiving surface.
2Object-generated harmful factors
If the developing device is separated from the photoconductive body before synchronous detection, then toner contamination is prevented, but the apparatus complexity increases
Solution Approach 1:
The patent employs a movable developing device that can dynamically switch between two positions: a first position where the developing sleeve contacts the photoconductive body for normal development, and a second position where the developing sleeve is separated from the photoconductive body during synchronous detection. This dynamic positioning prevents toner contamination during detection while maintaining simple apparatus structure through controlled movement.
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 effectively suppresses unnecessary exposure, reducing optical fatigue and ghost image formation while simplifying the apparatus configuration and reducing part count.
Implementation Method 1
an optical sensor configured to detect the light beam deflected by the deflector
Implementation Method 2
a photoconductive body configured to receive the light beam emitted by the light source and form an electrostatic latent image
Data Source
AI summary
An image forming apparatus includes a photoconductive body, a light source, a deflector to deflect a light beam from the light source, a scanning optical system to image the deflected light beam onto the photoconductive body, a developing unit to supply developer to the photoconductive body, an optical sensor to detect the deflected light beam, a moving mechanism to move the developing unit to a first position and to a second position, and a controller configured to start driving the deflector, when the developing unit is in the second position, the light source to emit the light beam, thereby obtaining a detection signal of the light beam from the optical sensor, and after obtaining the detection signal of the light beam from the optical sensor, control the moving mechanism to move the developing unit to the first position.