Image Forming Apparatus Radiation Reduction via Pixel Timing Differentiation
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Solution Overview
Problem
Existing image forming apparatuses generate significant unnecessary radiations during background exposure processing, leading to increased costs due to the need for additional clock generation circuits to suppress these radiations.
Innovation Solution
The image forming apparatus employs a signal generation unit that stores light-emission patterns for different density levels and generates light-emission signals to differentiate the light-emission start and termination timings between adjacent pixels, reducing periodic current flow in the laser driving circuit and minimizing unnecessary radiation generation without requiring a non-fixed frequency background exposure oriented clock generation circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a non-fixed frequency background exposure oriented clock generation circuit is added to reduce unnecessary radiations, then radiation noise is reduced, but device complexity and cost increase
Solution Approach 1:
The patent extracts the background exposure function from the fixed-frequency clock system by introducing a variable-frequency clock generation mechanism. The clock generation unit is modified to output clocks with different frequencies depending on whether background exposure or image formation is being performed, thereby separating the harmful periodic radiation effect from the necessary exposure function.
Solution Approach 2:
The patent applies dynamics by making the clock frequency variable rather than fixed. The clock generation unit dynamically adjusts its output frequency based on the operational mode (background exposure vs. image formation), preventing the light source from operating at a constant periodic interval that would generate unnecessary radiations while maintaining operational flexibility.
2Measurement precision
If pulse width modulation control is used to achieve minute light emission for background exposure, then exposure precision is improved, but high-frequency noise voltage is generated due to inductance in power source lines
Solution Approach 1:
The patent uses periodic pulse width modulation to control the light source, but crucially varies the period frequency between background exposure mode and image formation mode. This periodic control enables precise exposure amounts while the frequency variation prevents the generation of consistent high-frequency noise voltages that would occur with a fixed periodic signal.
3Ease of operation
If the light source emits light at constant intervals for background exposure, then background exposure processing is simplified, but unnecessary radiations are generated due to periodic current flow
Solution Approach 1:
The patent maintains operational simplicity by keeping the background exposure control logic straightforward, but introduces dynamic frequency variation in the clock signal. The system remains easy to operate with a clear mode-switching mechanism, while the dynamic clock frequency prevents the formation of consistent periodic current patterns that generate unnecessary radiations.
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 effectively reduces unnecessary radiation noise while maintaining image quality and stability, thereby lowering costs and improving the efficiency of the image forming process.
Implementation Method 1
a light irradiation unit configured to emit light based on a light-emission signal corresponding to an image to be formed and form a latent image by irradiating and scanning the charged photosensitive member with light
Implementation Method 2
An inductance component of the power source line induces a high-frequency noise voltage
Data Source
AI summary
An image forming apparatus includes a signal generation unit configured to generate a light-emission signal. The signal generation unit stores information relating to a toner non-adherent area oriented light-emission pattern having been set beforehand. The toner non-adherent area oriented light-emission pattern is a light-emission pattern that causes a light irradiation unit to emit light in such a way as to prevent toner particles from adhering to a photosensitive member. When the light irradiation unit scans respective portions corresponding to two pixels adjacently disposed in a scanning direction a based on a part of the light-emission signal generated based on the toner non-adherent area oriented light-emission pattern, at least one of (a) light-emission start timing of light irradiation unit and (b) light-emission termination timing of the light irradiation unit is differentiated between the two pixels.