Vinyl Copolymer Charge Generation Layer for Electrophotographic Photoreceptors
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Solution Overview
Problem
Electrophotographic photoreceptors experience image defects due to 'positive ghosting', where a portion of the image formed in one cycle appears dark in the next cycle, caused by charge carriers accumulating at charge traps in the charge generation layer.
Innovation Solution
Incorporating a vinyl copolymer with a chlorine-containing component, an acyloxy component, and a polycarboxyl component in the charge generation layer, where the proportion of the acyloxy component is between 13.4 mol% and 20.0 mol%, reducing the formation of charge traps and subsequent charge carrier accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional charge generation layer is used, then the photoreceptor can form images, but charge carriers accumulate at charge traps causing positive ghosting in the next image formation cycle
Solution Approach 1:
The patent changes the chemical composition parameters of the charge generation layer by incorporating a vinyl copolymer with specific structural units (chlorine-containing, acyloxy, and carboxyl groups) in controlled proportions. The acyloxy group proportion is specifically set between 13.4-20.0 mol%, which modifies the electrical properties of the layer to reduce charge carrier accumulation at traps, thereby eliminating positive ghosting while maintaining image formation capability.
Solution Approach 2:
The patent uses a composite vinyl copolymer material combining multiple structural units with different functional groups (chlorine-containing units for charge generation, acyloxy units for controlling charge carrier behavior, and carboxyl units for stability). This composite approach creates a charge generation layer that simultaneously achieves good charge generation performance and reduced charge trap formation, preventing positive ghosting.
2Object-generated harmful factors
If the proportion of acyloxy group is too low, then charge traps form and cause positive ghosting, but if too high, then other performance parameters deteriorate
Solution Approach 1:
The patent identifies and optimizes the critical parameter of acyloxy group proportion in the vinyl copolymer, setting it within the specific range of 13.4-20.0 mol%. This parameter optimization balances two opposing requirements: having enough acyloxy groups to suppress charge trap formation and prevent positive ghosting, while maintaining other essential photoreceptor performance characteristics. The precise quantification of this compositional parameter enables consistent reproduction of the desired effect.
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 minimizes the occurrence of positive ghosting, leading to reduced image defects by limiting the partial reduction in surface potential of the photoreceptor.
Implementation Method 1
a charge generation layer disposed on the conductive support, the charge generation layer including a charge generating material
Data Source
AI summary
An electrophotographic photoreceptor includes a conductive support, a charge generation layer disposed on the conductive support, and a charge transport layer disposed on the charge generation layer. The charge generation layer includes a charge generating material and a vinyl copolymer. The vinyl copolymer includes a structural unit including a chlorine atom, a structural unit including an acyloxy group, and a structural unit including two or more carboxyl groups. The proportion of the structural unit including an acyloxy group to all of the structural units is 13.4 mol % or more and 20.0 mol % or less. The charge transport layer includes a charge transporting material and a binder resin.