Photoreceptor Cleaning Blade Structure for Density Unevenness Control
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Solution Overview
Problem
Existing image forming apparatuses experience density unevenness and filming on the photoreceptor surface due to increased frictional force between the photoreceptor and cleaning blade, leading to unstable blade behavior and deteriorated cleaning properties.
Innovation Solution
The image forming apparatus incorporates a photoreceptor with a surface layer containing a polyarylate resin and a cleaning blade with a dual-layer polyurethane structure, where the first layer is hard (85-95 degrees) and the second layer is soft (55-70 degrees), stabilizing blade behavior and improving cleaning properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cleaning blade hardness is increased to improve cleaning performance, then cleaning properties are improved, but frictional force increases causing density unevenness and filming
Solution Approach 1:
The cleaning blade is designed with a dual-layer structure where the first polyurethane layer (contact layer) has hardness of 85-95 degrees for effective cleaning, while the second polyurethane layer (support layer) has hardness of 55-70 degrees to reduce friction. This local differentiation of material properties allows the blade to perform cleaning function effectively while minimizing harmful frictional effects on the photoreceptor surface.
Solution Approach 2:
The cleaning blade combines two different polyurethane materials with distinct hardness characteristics to create a composite structure. The harder first layer provides cleaning effectiveness, while the softer second layer reduces frictional force and prevents filming. This composite approach resolves the contradiction between cleaning performance and friction reduction.
2Stability of the object's composition
If the cleaning blade hardness is increased to stabilize blade behavior, then cleaning performance is improved, but abrasion resistance of photoreceptor deteriorates
Solution Approach 1:
The first polyurethane layer with hardness of 85-95 degrees is positioned at the contact surface to provide stable blade behavior and effective cleaning, while the second polyurethane layer with hardness of 55-70 degrees serves as a support layer that reduces abrasion on the photoreceptor. This localized differentiation allows the blade to maintain stability without causing excessive wear.
3Reliability
If a single-layer hard cleaning blade is used to improve cleaning properties, then cleaning performance is improved, but blade tip stability deteriorates
Solution Approach 1:
The dual-layer polyurethane structure combines a hard first layer (85-95 degrees) for cleaning effectiveness with a softer second layer (55-70 degrees) that provides flexibility and stability to the blade tip. The softer support layer allows the blade to conform to the photoreceptor surface while maintaining stable behavior, preventing the blade tip from becoming too rigid and unstable.
Data Source
AI summary
An image forming apparatus includes a photoreceptor, a charging device that charges a surface of the photoreceptor, an electrostatic latent image forming device that forms an electrostatic latent image on the charged surface of the photoreceptor, a developing device that contains a developer containing a toner and develops the electrostatic latent image formed on the surface of the photoreceptor to form a toner image, a transfer device that transfers the toner image to a surface of a recording medium, and a cleaning device that has a cleaning blade coming into contact with the surface of the photoreceptor to clean the surface of the photoreceptor, in which the toner contains toner particles, titanate compound particles, and silica particles, a surface layer of the photoreceptor contains a polyarylate resin that has a dicarboxylic acid unit (A) represented by Formula (A) and a diol unit (B) represented by Formula (B), and the cleaning blade has a first polyurethane layer that is a layer coming into contact with the photoreceptor and has a hardness of 85 degrees or more and 95 degrees or less, and a second polyurethane layer that is a layer supporting the first polyurethane layer and has a hardness of 55 degrees or more and 70 degrees or less.In Formula (A), ArA1 and ArA2 are each independently an aromatic ring which may have a substituent, LA is a single bond or a divalent linking group, and nA1 is 0, 1, or 2.In Formula (B), ArB1 and ArB2 are each independently an aromatic ring which may have a substituent, LB is a single bond, an oxygen atom, a sulfur atom, or —C(Rb1)(Rb2)—, and nB1 is 0, 1, or 2, where Rb1 and Rb2 are each independently a hydrogen atom, an alkyl group having 1 or more and 20 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an aralkyl group having 7 or more and 20 or less carbon atoms, and Rb1 and Rb2 may be bonded to each other to form a cyclic alkyl group.