Phthalocyanine Crystal Humidity Stability via Aromatic Aldehyde Conversion
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Solution Overview
Problem
Phthalocyanine crystals with high sensitivity exhibit significant fluctuations in sensitivity due to humidity changes, leading to inconsistent image quality in electrophotographic devices, particularly in full-color laser printers and copying machines, where water molecules act as sensitizers and can be eliminated at low humidity, affecting image density and color tone.
Innovation Solution
Converting the crystal form of phthalocyanine crystal precursors using specific compounds such as aromatic aldehydes, organic acids, or oxygen-containing halogenated aromatic compounds to stabilize the crystal structure and maintain sensitivity across varying humidity levels, resulting in an electrophotographic photoreceptor with consistent performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If phthalocyanine crystals are used as charge generation substance for high sensitivity, then sensitivity to exposure light is improved, but sensitivity fluctuates significantly with humidity changes
Solution Approach 1:
The patent introduces water molecules as an intermediary substance that mediates between the phthalocyanine crystal and exposure light. These water molecules act as sensitizers that enhance light absorption and charge generation efficiency, while the crystal structure controls their retention to maintain stability under humidity changes
Solution Approach 2:
The patent changes the crystal structure parameters of phthalocyanine to create specific crystal forms (α, β, γ, δ) with different molecular arrangements. These structural parameter changes affect how water molecules are incorporated and retained in the crystal, thereby controlling both sensitivity and humidity stability
2Use of energy by moving object
If water molecules are incorporated as sensitizers in phthalocyanine crystals, then charge generation efficiency is improved, but sensitivity decreases at low humidity conditions
Solution Approach 1:
The patent employs prior cushioning by incorporating water molecules into the crystal structure during manufacturing, creating a buffer that maintains sensitivity stability. The crystal structure is designed to retain these water molecules under varying humidity conditions, cushioning against sensitivity fluctuations before they occur
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 converted phthalocyanine crystals demonstrate high sensitivity with minimal fluctuation in response to humidity changes, ensuring stable image quality across different environmental conditions, addressing the issue of inconsistent image density and color tone in electrophotographic devices.
Implementation Method 1
As an electrophotographic photoreceptor (hereinafter, optionally abbreviated as 'photoreceptor') that is the core of the electrophotography technology, photoreceptors using inorganic photoconductors such as selenium, arsenic-selenium alloy, and zinc oxide have been conventionally employed but recently, the mainstream becomes the photoreceptors using organic photoconductive materials
Implementation Method 2
With regard to the phthalocyanine compounds, it is reported that even if the structure of the individual molecule is identical, a phthalocyanine compound may different in charge generation efficiency according to the regularity (crystal form) in arrangement of crystal, which is an agglomerate of molecules
Data Source
AI summary
Provided is an excellent phthalocyanine crystal having high sensitivity and little fluctuation in sensitivity for a humidity change in a use environment and applicable to the martial for solar battery, electronic paper, electrophotographic photoreceptor, etc. Namely, phthalocyanine crystal obtained by bringing a phthalocyanine crystal precursor into contact with an aromatic aldehyde compound to convert the crystal form. Also, provided is an electrophotographic photoreceptor that not only exhibits high sensitivity but also has little fluctuation in sensitivity for a humidity change in a use environment. Further, provided is an electrophotographic photoreceptor cartridge and an image-forming device, both of which can produce a stable quality images for a humidity change in a use environment by using the electrophotographic photoreceptor.