Photosensitive Drum Exposure Control for Mixed-Media Print Defects
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Solution Overview
Problem
Existing image formation technologies face challenges in handling various types of media, such as continuous and irregular shape media, leading to printing defects due to charge accumulation on the photosensitive drum when transferring images to media with high volume resistivity.
Innovation Solution
A drum unit is designed with a photosensitive drum and frame that adheres to the equation ΔV≤0.489×Q−0.014(%), where ΔV represents the change in surface potential, ensuring effective handling of diverse media and reducing printing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If exposure processing is performed to increase surface potential in the out-of-medium region, then printing defects are reduced, but it becomes difficult to handle various types of media such as continuous medium and irregular shape medium
Solution Approach 1:
The patent applies preliminary action by performing exposure processing in the out-of-medium region before the transfer process. This pre-exposure increases the absolute value of surface potential in advance, preventing charge accumulation that would otherwise cause printing defects like strong transfer history. The exposure is performed at a specific exposure amount (0.05 to 0.5 μJ/cm²) to achieve the desired surface potential without causing harmful effects.
Solution Approach 2:
The patent applies parameter changes by carefully controlling the exposure amount within a specific range (0.05 to 0.5 μJ/cm²). This parameter optimization allows the system to increase surface potential sufficiently to prevent printing defects while avoiding over-exposure that would cause charging defects. The dual parameter control of exposure amount and circumferential speed enables versatile handling of different media types.
2Reliability
If exposure amount is increased to suppress charge accumulation, then printing defects are reduced, but charging defects may occur on the photosensitive drum surface
Solution Approach 1:
The patent applies parameter changes by precisely controlling the exposure amount within the optimal range of 0.05 to 0.5 μJ/cm². This parameter optimization ensures that sufficient exposure is provided to increase surface potential and suppress charge accumulation, while simultaneously avoiding excessive exposure that would cause charging defects such as image density variation or surface damage. The circumferential speed is also controlled at 50 to 150 mm/s to coordinate with the exposure amount for optimal results.
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
The solution effectively suppresses printing defects across different media types, enhancing the versatility and reliability of image formation processes.
Implementation Method 1
a surface of a photosensitive drum is charged and then exposed with light, so that an electrostatic latent image is formed on the surface of the photosensitive drum
Implementation Method 2
a surface of a photosensitive drum is charged and then exposed with light, so that an electrostatic latent image is formed on the surface of the photosensitive drum
Implementation Method 3
A transfer voltage is applied to the transfer member, the developer image on the photosensitive drum is transferred to the medium
Data Source
AI summary
A drum unit including a photosensitive drum may satisfy an equation of ΔV≤0.489×Q−0.014 (%), where ΔV={1−(V1/V0)}×100 (%). V0 is a surface potential of the photosensitive drum that is measured under a first condition that exposes a surface of the photosensitive drum at an exposure amount Q in a range of 0.13 to 0.34 μJ/cm2 while the photosensitive drum is rotated at a circumferential speed of 151 mm/s with the surface of the photosensitive drum being charged with a voltage having 1000 volts and a first polarity. V1 is a surface potential of the photosensitive drum that is measured under the first condition again after the surface of the photosensitive drum is applied for 406 seconds with a voltage having 2850 volts and a second polarity while the photosensitive drum is rotated at the circumferential speed of 73 mm/s.