Electrostatic Latent Image Evaluation Device for Photoreceptors
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Solution Overview
Problem
Conventional methods fail to accurately evaluate electrostatic latent images on electrophotographic photoreceptors due to low distance resolution and inability to handle dark decay, limiting the quality of image formation in devices like digital PPCs and laser printers.
Innovation Solution
An electrostatic latent image evaluation device and method using an optical scanner and electron gun to form and evaluate electrostatic latent images on photoreceptors, calculating sizes and spatial frequencies of images formed with varying exposure energy densities, and assessing electric potential distributions for precise evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an electron beam method with 1 micron distance resolution is used, then measurement precision is improved, but the method cannot handle high electric potentials of several hundred to several thousand volts
Solution Approach 1:
The patent modifies the electron beam parameters, specifically setting the acceleration voltage to a value lower than the surface potential of the dielectric body. This parameter change allows the electron beam to be repelled by the high positive potential, enabling the measurement of electrostatic latent images on electrophotographic photoreceptors that operate at several hundred to several thousand volts, thus achieving both high resolution and compatibility with high potentials.
2Loss of time
If imaging is delayed after forming electrostatic latent image, then preparation time is improved, but dark decay causes surface potential to decrease and image quality deteriorates
Solution Approach 1:
The patent applies preliminary action by immediately applying a negative potential to the dielectric body surface right after the electrostatic latent image is formed, before any significant dark decay can occur. This preliminary potential application preserves the electrostatic latent image by counteracting the natural decay process, allowing sufficient time for vacuum chamber preparation and electron beam system stabilization without image quality deterioration.
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
Enables high-resolution evaluation of electrostatic latent images, improving image quality by setting optimal specifications for each process stage, reducing costs, and extending the evaluation capability beyond conventional limitations.
Implementation Method 1
an electron gun configured to irradiate a charged particle beam on the photoreceptor sample having an electrostatic latent image
Implementation Method 2
a detector configured to detect an electron emitted from the photoreceptor sample by the irradiation of the charged particle beam
Implementation Method 3
an optical scanner configured to irradiate laser light of a wavelength of 400 nm-800 nm on a photoreceptor sample, and form an electrostatic latent image
Data Source
AI summary
An electrostatic latent image evaluation device includes an optical scanner configured to irradiate laser light of a wavelength of 400 nm-800 nm on a photoreceptor sample, and form an electrostatic latent image, an electron gun configured to irradiate a charged particle beam to the photoreceptor sample having the electrostatic latent image, and surface electric charge distribution or surface electric potential distribution, a detector configured to detect an electron emitted from the photoreceptor sample by the irradiation of the charged particle beam, and an electrostatic latent image evaluation section configured to calculate sizes of a plurality of electrostatic latent images formed by the laser light each having different exposure energy density according to a detection signal detected by the detector, and evaluate the electrostatic latent image according to a change in the calculated sizes.