Laser Exposure Control for Charge Potential in Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses employing the electrophotographic method face challenges in simplifying the configuration for controlling the charge potential of photosensitive members, especially when dealing with varying process speeds and media types, leading to complex operation and control.
Innovation Solution
An image forming apparatus with a photosensitive member, a light illumination unit, and a control unit that performs normal and weak exposures to manage toner attachment, allowing for two modes of operation based on different drum speeds without thinning the scanning surface, ensuring appropriate charge potential control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-exposure lamp is used to control charge potential, then charge potential control is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the pre-exposure function from a separate lamp component and integrates it into the existing laser exposure apparatus. The laser beam is used for both image formation and pre-exposure by controlling its emission timing and intensity, eliminating the need for a dedicated pre-exposure lamp and simplifying the overall apparatus configuration.
Solution Approach 2:
The laser exposure apparatus is designed to perform multiple functions: it forms the electrostatic latent image during normal operation and also serves as the pre-exposure light source when needed. By controlling the laser emission timing and intensity, the same component achieves both image formation and charge potential control functions.
2Adaptability or versatility
If the printer is designed to handle various media types and processing speeds, then adaptability is improved, but operation and control complexity increases
Solution Approach 1:
The patent implements dynamic adjustment of laser beam intensity and exposure timing based on the detected media type and required processing speed. The control unit modifies exposure parameters in real-time according to the paper properties, allowing the printer to adapt to various media types and speeds through software control rather than hardware complexity.
Solution Approach 2:
The system changes exposure parameters (intensity, duration, timing) of the laser beam according to the media type and processing speed requirements. By adjusting these parameters dynamically, the printer achieves adaptability to different media without requiring complex mechanical or structural modifications.
3Manufacturing precision
If weak exposure is performed without thinning the scanning surface, then image quality is improved, but productivity decreases at first mode speed
Solution Approach 1:
The patent applies periodic thinning of the scanning surface during weak exposure operations. Instead of continuously scanning all surfaces, the system selectively skips certain scanning surfaces in a periodic pattern, reducing the total exposure time while still achieving adequate pre-exposure效果. This maintains image quality while improving processing speed efficiency.
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 enables simplified and effective control of charge potential on photosensitive members across different process speeds and media types, enhancing operational efficiency and image quality.
Implementation Method 1
a light illumination unit which includes a light emitting element and a deflection scanning unit and is configured to reflect light emitted from the light emitting element from a scanning surface of the deflection scanning unit such that the photosensitive member which is charged is illuminated
Implementation Method 2
a development unit configured to form a toner image by attaching toner to a latent image formed on the photosensitive member illuminated by the light illumination unit
Data Source
AI summary
An image forming apparatus includes a control unit. The control unit is capable of executing a first mode for forming a toner image on the photosensitive member that rotates at a first speed and a second mode for forming a toner image on the photosensitive member that rotates at a second speed slower than the first speed, and the control unit causes the light illumination unit to perform the weak exposure in the first mode without thinning the scanning surface of the deflection scanning unit and perform the weak exposure in the second mode while thinning the scanning surface of the deflection scanning unit.