Secondary Transferrer Nip Time Adjustment for Toner Transfer
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Solution Overview
Problem
Image forming devices face challenges in securing good transferability of toner images onto various recording media with different thicknesses and materials, as existing methods struggle to maintain transfer efficiency due to variations in capacitance and resistance, leading to issues like electric discharge and inadequate toner transfer.
Innovation Solution
The implementation of an image forming device with an endless intermediate transfer belt and a secondary transferrer that adjusts the nip time and time constant based on the capacitance of the recording medium, using a sheet detector to acquire capacitance data and adjust the system speed, thereby optimizing the transfer process without increasing applied voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the applied voltage is increased to improve toner transfer efficiency, then transferability is improved, but electric discharge occurs and damages the recording medium
Solution Approach 1:
The patent changes the temporal parameters of the transfer process by dynamically adjusting the nip time based on the capacitance characteristics of different recording media. For media with high capacitance (like thin films), the nip time is extended to allow sufficient charge accumulation at lower voltages, preventing electric discharge while maintaining transfer efficiency. This parameter adjustment resolves the contradiction between achieving good transferability and avoiding harmful electric discharge.
Solution Approach 2:
The patent implements a feedback control mechanism where the capacitance of the recording medium is detected first, and based on this detection, the nip time is automatically adjusted before the transfer process begins. This feedback loop ensures that each transfer operation uses optimized parameters specific to the medium being used, preventing electric discharge while maintaining high transfer efficiency across different media types.
2Reliability
If the nip time is extended to improve charge accumulation, then transfer efficiency is improved, but the system speed decreases
Solution Approach 1:
The patent applies dynamics by making the nip time adjustable rather than fixed. The system dynamically changes the nip time based on the detected capacitance characteristics of the recording medium. For high-capacitance media, longer nip times are used to ensure complete charge accumulation and high transfer efficiency. For low-capacitance media, shorter nip times maintain high system speed. This dynamic adjustment resolves the contradiction between transfer efficiency and productivity.
3Reliability
If the time constant is reduced to improve charge accumulation speed, then transfer efficiency is improved, but the resistance of the transfer components must be reduced
Solution Approach 1:
The patent changes the time constant parameter by adjusting either the resistance or capacitance components in the transfer system. For recording media with high capacitance, the system reduces the time constant (by adjusting resistance or adding capacitance in parallel) to speed up charge accumulation, ensuring efficient transfer without requiring complex resistance control mechanisms across all components.
4Device complexity
If a fixed transfer system is used for all recording media, then device complexity is reduced, but transferability varies across different media types
Solution Approach 1:
The patent maintains relatively simple device structure while achieving high transferability across different media types by dynamically changing operational parameters (nip time and time constant) based on capacitance detection. This approach avoids the need for multiple specialized transfer systems for different media, resolving the contradiction between device simplicity and universal transferability.
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 solution ensures high transfer efficiency for diverse recording media by extending the nip time or reducing the time constant, preventing electric discharge and ensuring complete toner transfer, even with media of varying thickness and material properties.
Implementation Method 1
a value calculated from Rtotal×Ctotal by using the combined resistance Rtotal and the combined capacitance Ctotal is defined as a time constant τ [sec], and the image forming device further comprises: a sheet detector that acquires capacitance of the recording medium
Implementation Method 2
a secondary transferrer that transfers a toner image carried by the intermediate transfer belt to a recording medium, wherein the secondary transferrer includes a secondary transfer roller and a counter roller that faces the secondary transfer roller and forms a secondary transfer nip
Data Source
AI summary
An image forming device includes: an endless intermediate transfer belt; and a secondary transferrer, wherein the secondary transferrer includes a secondary transfer roller and a counter roller, a value calculated from w/Vsys is defined as a nip time N [sec], when the secondary transferrer is deemed as an equivalent circuit including a resistance R1 [Ω·m2] of the secondary transfer roller, a resistance R2 [Ω·m2] of the intermediate transfer belt, a resistance R3 [Ω·m2] of the counter roller, and capacitance Cmed [F/m2] of a recording medium, in a case where a combined resistance in the equivalent circuit is defined as Rtotal [Ω·m2], and combined capacitance in the equivalent circuit is defined as Ctotal [F/m2], a value calculated from Rtotal×Ctotal is defined as a time constant τ [sec], and the image forming device further includes: a sheet detector; and a hardware processor.