Toner Transfer Guide Unit and Viscoelastic Binder for Image Quality
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Solution Overview
Problem
In intermediate transfer-type image forming apparatuses, toner transfer properties are deteriorated due to discharge generation upstream of the primary transfer position, leading to toner scattering and increased non-electrostatic adhesion, especially under high temperature and high humidity conditions or when forming images with low density or on both surfaces of a recording medium.
Innovation Solution
An image forming apparatus is designed with a guide unit that aligns the image holding member and intermediate transfer member via a toner image before primary transfer, using a toner with a binder resin containing crystalline polyester and external additives, ensuring a mechanical loss tangent within specific ranges to maintain toner elasticity and prevent adhesion to the image holding member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a guide unit is provided to align the image holding member and intermediate transfer member upstream of the primary transfer position, then toner image transfer quality is improved, but device complexity increases
Solution Approach 1:
A guide unit is introduced as an intermediary component between the image holding member and the intermediate transfer member. This guide unit aligns the peripheral surfaces of these members upstream of the primary transfer position, ensuring proper positioning before toner transfer occurs. The guide unit acts as a mediator that facilitates accurate alignment without requiring complex control systems or multiple adjustment mechanisms.
2Object-generated harmful factors
If the toner has high elasticity (tan δP1 ≥ 2) to prevent adhesion to the image holding member, then toner scattering is reduced, but transfer efficiency may deteriorate
Solution Approach 1:
The toner's mechanical loss tangent (tan δP1) is controlled within a specific range (0.5 ≤ tan δP1 < 2) by adjusting the binder resin composition and molecular weight. This parameter optimization ensures the toner has appropriate elasticity to prevent adhesion to the image holding member while maintaining sufficient transfer efficiency. The binder resin is selected with specific glass transition temperature and molecular weight characteristics to achieve the desired tan δP1 value.
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 prevents toner image deterioration during transfer, maintaining high-quality image formation even under challenging conditions, such as high temperature and humidity, and during continuous printing on both sides of a recording medium.
Implementation Method 1
the toner contains a toner particle which contains a binder resin containing a crystalline polyester resin... and satisfies the following Expression (1): 2≤tan δP1≤2.5 wherein tan δP1 represents a maximum value of a mechanical loss tangent existing in a range where a complex elastic modulus is from 1×106 Pa to 1×108 Pa
Data Source
AI summary
An image forming apparatus includes a guide unit that guides at least one of an image holding member and an intermediate transfer member to a primary transfer position provided by a primary transfer unit such that a portion of the surface of the image holding member and a portion of the surface of the intermediate transfer member are disposed along with each other, wherein a toner contains a toner particle which contains a binder resin containing a crystalline polyester resin, a coloring agent and a releasing agent, and an external additive, and satisfies Expression: 2≤tan δP1≤2.5, wherein tan δP1 represents a maximum value of a mechanical loss tangent existing in a range where a complex elastic modulus is from 1×106 Pa to 1×108 Pa, which is measured at an angular frequency of 6.28 rad/sec and a strain amount of 0.3%.