Laser Light Irradiation Control for Image Quality in Electrophotography
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Solution Overview
Problem
Image forming apparatuses using electrophotography struggle to maintain high image quality due to variations in laser light emission, leading to unsuitable light quantities during minute emission, which can result in image defects like fogging and toner adhesion issues.
Innovation Solution
The apparatus incorporates a light irradiating device with a determining unit that adjusts the light source to emit normal light quantities for image portions and minute light quantities for non-image portions, using a laser driving circuit to control the emission levels based on reference values and light quantity adjustments, ensuring suitable potentials on the photosensitive member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser light is emitted at normal emission level to ensure sufficient light quantity for image formation, then image quality is maintained, but fogging occurs on non-image portions due to excessive light quantity
Solution Approach 1:
The patent applies local quality by differentiating light emission levels between image and non-image portions. The light irradiating device emits laser light at a first emission level for image portions requiring toner adhesion and at a second emission level (lower than the first) for non-image portions to prevent fogging, thereby optimizing local conditions for each region
Solution Approach 2:
The patent changes the emission level parameter of the laser light source based on the imaging state. The determining unit adjusts the emission level between a first level for normal image formation and a second level for preventing fogging, dynamically modifying the light parameter to match different operational requirements
2Object-affected harmful factors
If laser light emission is reduced to minute levels to prevent fogging on non-image portions, then fogging is suppressed, but light quantity becomes insufficient for proper image formation
Solution Approach 1:
The patent applies local quality by differentiating light emission levels between image and non-image portions. The light irradiating device emits laser light at a first emission level for image portions requiring toner adhesion and at a second emission level (lower than the first) for non-image portions to prevent fogging, thereby optimizing local conditions for each region
Solution Approach 2:
The patent applies partial action by providing sufficient light quantity only where needed (image portions) rather than uniformly across the entire photosensitive member. The determining unit controls the light irradiating device to emit at a first emission level for image portions and a second emission level for non-image portions, optimizing light distribution
3Device complexity
If a single light emission level is used for both image and non-image portions, then device complexity is reduced, but image quality deteriorates due to inability to prevent fogging
Solution Approach 1:
The patent applies universality by enabling the light irradiating device to perform multiple functions: image formation at a first emission level and fogging prevention at a second emission level. The determining unit controls the device to switch between these functions based on the imaging state, allowing one device to handle multiple operational requirements
Solution Approach 2:
The patent applies feedback through the determining unit that monitors the imaging state and adjusts the emission level accordingly. The system receives information about whether toner adhesion is occurring and dynamically modifies the light emission level to maintain optimal image quality while preventing fogging
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 configuration effectively suppresses image defects such as fogging and toner adhesion, maintaining high image quality by optimizing light emission levels on both image and non-image areas of the photosensitive member.
Implementation Method 1
an optical scanning device configured to condense laser light emitted from a laser diode to form an image on a photosensitive member by a lens
Implementation Method 2
condense laser light emitted from a laser diode to form an image on a photosensitive member by a lens
Implementation Method 3
laser light emitted from behind the chip is received at a photodiode disposed behind the chip
Implementation Method 4
causes the light source to emit light with normal emitted light quantity sufficient for adhering toner on an image portion of the photosensitive member, and causes the light source to emit light with minute emitted light quantity smaller than normal emitted light quantity sufficient for preventing toner from being adhered on a non-image portion
Data Source
AI summary
A light irradiating device causes a light source to emit light with normal emitted light quantity sufficient for adhering toner on a photosensitive member, on an image portion of the photosensitive member, and causes the light source to emit light with minute emitted light quantity sufficient for preventing toner from being adhered on the photosensitive member, which is smaller than normal emitted light quantity. The light irradiating device includes a determining unit to determine a reference value input to the light irradiating device. Minute emitted light quantity is set based on the reference value input to the light irradiating device. The determining unit determines the reference value to be input to the light irradiating device based on information of relationship between a predetermined reference value and the light quantity in the position of the photosensitive member when causing the light source to emit light, based on the predetermined reference value.