Electrophotographic Photoreceptor Protective Layer Curing
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Solution Overview
Problem
Conventional electrophotographic photoreceptors exhibit low potential stability and wear resistance, particularly under severe conditions such as high line speed, low temperature, and low humidity, due to the absorption of ultraviolet rays by charge transporting materials used in the protective layer, which inhibits the curing reaction and polymerization of the binder resin.
Innovation Solution
Incorporating a charge transporting material with a maximal absorption wavelength of 405±50 nm and a photopolymerization initiator of a single-molecule system into the protective layer, where the free energy change (G) between the charge transporting material and the photopolymerization initiator satisfies the expression G=Eox(D/D+)−Ered(A−/A)−E*≤−0.2 eV, facilitating the sensitization of the photopolymerization initiator and enhancing the curing reaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a charge transporting material with high hole transportability is used in the protective layer, then potential stability is improved, but wear resistance deteriorates due to UV absorption inhibiting curing
Solution Approach 1:
The patent changes the absorption wavelength parameter of the charge transporting material from conventional ranges (absorbing UV curing light) to a specific range with maximal absorption wavelength of 405±50 nm. This parameter change allows the material to provide high hole transportability while avoiding interference with the photopolymerization curing process, thereby simultaneously achieving excellent potential stability and high wear resistance.
2Ease of manufacture
If ultraviolet rays are used for curing the protective layer, then the protective layer is formed, but the charge transporting material absorbs the ultraviolet rays and reduces polymerization reaction rate
Solution Approach 1:
The patent modifies the optical absorption parameter of the charge transporting material by selecting materials with maximal absorption wavelength of 405±50 nm. This parameter change creates a spectral separation between the charge transporting material's absorption band and the photopolymerization initiator's activation wavelength, allowing UV curing to proceed at high reaction rates without significant absorption by the charge transporting material.
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 results in an electrophotographic photoreceptor with excellent potential stability and high wear resistance, allowing for reduced maintenance frequency and high-quality image formation even under severe conditions.
Implementation Method 1
the protective layer includes a cured product of a composition containing a radically polymerizable compound, a charge transporting material, and a photopolymerization initiator of a single-molecule system
Implementation Method 2
a charge transporting material exhibiting a maximal absorption wavelength of 405±50 nm and a photopolymerization initiator of a single-molecule system... satisfying a specific expression regarding the charge transporting material and the photopolymerization initiator
Data Source
AI summary
An electrophotographic photoreceptor according to the present invention includes a conductive support, a photosensitive layer, and a protective layer disposed in sequence. The protective layer includes a cured product of a composition containing a radically polymerizable compound, a charge transporting material exhibiting a maximal absorption wavelength of 405±50 nm, and a photopolymerization initiator of a single-molecule system; and a following Expression (A) is satisfied:G=Eox(D/D+)−Ered(A−/A)−E*≤−0.2 [eV] Expression (A):G represents a free energy change, Eox(D/D+) represents an oxidation potential of the charge transporting material, Ered(A−/A) represents a reduction potential of the photopolymerization initiator, and E* represents an excitation energy of the charge transporting material.