Driving Roller Eccentricity Compensation via Synchronous Waveform Weakening
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Solution Overview
Problem
Conventional electrophotographic image forming apparatuses face image position accuracy degradation due to eccentricity in the driving roller, which cannot be fully corrected when slip occurs between the driving roller and the belt, especially under increased load conditions.
Innovation Solution
An image forming apparatus with a detector to sense a desired point on the driving roller and a hardware processor that acquires and processes waveform signals to generate a drive signal that cancels the synchronous waveform signal synchronized with the roller's revolution, thereby adjusting the drive source to mitigate eccentricity-induced position shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an encoder roller with eccentric component removing unit is used to detect and correct position/velocity changes, then registration shift and uneven development are prevented, but the system cannot cancel eccentric components if slip occurs between the driving roller and belt due to increased load
Solution Approach 1:
The patent replaces the mechanical encoder-based detection system with a non-contact optical measurement system. A line sensor detects the position of a mark on the intermediate transfer belt, and a CPU calculates circumferential velocity and eccentric components from the positional data, eliminating the need for physical contact between encoder and roller surface.
Solution Approach 2:
The patent introduces a mark as an intermediary element attached to the intermediate transfer belt. This mark serves as a reference point that can be optically detected to infer the belt's position and velocity, indirectly measuring the driving roller's performance without direct contact.
2Manufacturing precision
If the driving roller is made highly precise to eliminate eccentricity, then image position accuracy is maintained, but manufacturing costs and device complexity increase
Solution Approach 1:
The patent implements a feedback control system where the line sensor continuously monitors the mark position on the intermediate transfer belt, the CPU calculates eccentric components from this data, and the results are used to correct the driving roller's operation, creating a closed-loop system that actively compensates for eccentricity.
Solution Approach 2:
The patent changes the operational parameters of the driving roller dynamically by adjusting its circumferential velocity based on detected eccentric components. The system calculates correction values and modifies the driving roller's rotation speed to compensate for position deviations caused by eccentricity.
Data Source
AI summary
An image forming apparatus includes: a driving roller that conveys a paper sheet; a detector that detects a desired point on the driving roller; and a hardware processor that: acquires a waveform signal indicating one of a change in an image forming position with respect to the paper sheet and a change in a sheet conveyance velocity; extracts a synchronous waveform signal from the waveform signal acquired by the hardware processor, the synchronous waveform signal being synchronized with one revolution of the driving roller, the one revolution being detected by the detector; and inputs a drive signal to a drive source of the driving roller, the drive signal being input to weaken an amplitude of the synchronous waveform signal extracted by the hardware processor.