Image Forming Apparatus Speed Control via Reference Photoreceptor
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately detecting periodic unevenness in photosensitive drums due to variations in the intermediate transfer member's surface speed and deformation of optical components, leading to misregistration and deteriorated image quality.
Innovation Solution
The apparatus includes a first and second image forming unit, an intermediate transfer member, sensors to measure images on both the photoreceptor and transfer member, and a controller that controls the formation and measurement of reference and measurement images using different color toners, allowing for precise detection and correction of periodic unevenness by adjusting the rotation speed of the photoreceptors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the intermediate transfer member is driven by a predetermined driving roller, then the images are transferred sequentially from each photoreceptor, but the surface speed varies due to eccentricity and thickness unevenness, causing measurement errors
Solution Approach 1:
The patent introduces a reference photoreceptor as an intermediary standard for speed comparison. By measuring the interval of reference images on the reference photoreceptor and comparing it with the interval of measurement images on the intermediate transfer member, the system can detect speed variations without being directly affected by the intermediate transfer member's eccentricity and thickness unevenness. This intermediary reference allows accurate detection of periodic unevenness despite the unstable drive conditions.
2Device complexity
If the driving roller diameter is similar to that of the photoreceptor, then the structure is compact, but the disturbance period matches the photoreceptor rotation period, making it difficult to detect periodic unevenness
Solution Approach 1:
The patent separates the measurement function into two independent parts: reference images formed on the reference photoreceptor and measurement images formed on the intermediate transfer member. This segmentation allows the system to distinguish between speed variations caused by the intermediate transfer member drive and actual periodic unevenness of the photoreceptor, even when the driving roller diameter is similar to the photoreceptor diameter.
3Manufacturing precision
If auto registration is performed using detection images on the intermediate transfer member, then misregistration is corrected, but periodic unevenness cannot be detected due to speed variations
Solution Approach 1:
The patent implements a feedback mechanism where the interval of reference images measured on the reference photoreceptor is used as a baseline to detect speed variations. This feedback allows the system to distinguish between speed variations (which affect all measurements equally) and actual periodic unevenness (which appears as deviations from the expected pattern), enabling both misregistration correction and periodic unevenness detection.
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 enables high-accuracy detection and correction of periodic unevenness, improving image quality by minimizing misregistration and ensuring precise superimposition of color images on the recording material.
Implementation Method 1
a first sensor configured to measure measurement images on the first photoreceptor; a second sensor configured to measure measurement images on the intermediate transfer member
Data Source
AI summary
An image forming apparatus includes a first sensor configured to measure measurement images on a first photoreceptor, a second sensor configured to measure measurement images on an intermediate transfer member, and a controller. The controller controls a first image forming unit to form first measurement images, wherein the first measurement images are formed along a rotation direction of the first photoreceptor, and controls the first sensor to measure the first measurement images on the first photoreceptor. The controller further controls the first image forming unit and a second image forming unit to form a plurality of measurement images while a rotation speed of the first photoreceptor is being controlled based on a measurement result of the first sensor, wherein the plurality of measurement images are formed along the predetermined direction of the intermediate transfer member.