Dual Roller Sheet Loop Stabilizes Image Reading Accuracy
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Solution Overview
Problem
Existing image formation systems face inaccuracies in image quality examination due to fluctuations in sheet conveyance speed caused by errors in roller positioning, mechanical wear, and thermal contraction, which affect the correct determination of image section positions on the recording medium.
Innovation Solution
The system incorporates a pair of conveying rollers with a first motor setting a conveying speed and a second pair with a slower speed, forming a loop to stabilize sheet conveyance between them, using guiding members to absorb shocks and maintain consistent speed, thereby minimizing pixel shifts and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single conveying mechanism is used to transport the sheet, then the device complexity is reduced, but the sheet conveyance speed fluctuates due to mechanical errors and wear, reducing measurement precision
Solution Approach 1:
The conveying mechanism is divided into two separate pairs of conveying rollers (first pair and second pair) with different functions. The first pair transports the sheet from the image forming apparatus, while the second pair feeds the sheet to the image reading apparatus. This segmentation allows each pair to be optimized for its specific function and reduces the impact of mechanical errors on overall conveyance precision.
Solution Approach 2:
A loop structure is introduced as an intermediary element between the two conveying roller pairs. The loop absorbs speed fluctuations and mechanical variations, acting as a buffer that decouples the conveying actions from the reading process. This allows the image reading apparatus to operate at a constant speed while the image forming apparatus can vary its conveying speed without directly affecting measurement precision.
2Productivity
If the conveying speed is increased to improve productivity, then the output increases, but the sheet conveyance speed fluctuates more, reducing measurement precision
Solution Approach 1:
The system employs dynamic speed control where the first conveying roller pair can operate at variable speeds to match the image forming apparatus output, while the second conveying roller pair maintains a constant speed optimized for accurate reading. The loop structure dynamically absorbs speed variations, allowing high productivity without compromising measurement precision.
3Measurement precision
If mechanical components are made more precise to reduce conveyance speed fluctuation, then measurement precision improves, but the device complexity and manufacturing cost increase
Solution Approach 1:
The loop structure serves as a mechanical intermediary that absorbs speed fluctuations without requiring ultra-precise mechanical components. By introducing this buffer zone, the system achieves high measurement precision through control strategy rather than through expensive, complex mechanical precision, thereby reducing overall device complexity.
Data Source
AI summary
An image forming system includes an image forming apparatus and an image reading apparatus. The image forming apparatus includes an image forming unit, a first pair of conveying rollers and a first motor driving the first pair of conveying rollers at a first speed. The image reading apparatus includes an image reading unit, a second pair of conveying rollers arranged downstream of said first pair of conveying rollers and a second motor driving the second pair of conveying rollers at a second speed lower than the first speed. The second motor drives the second pair of conveying rollers at the second speed so as to form a loop of the sheet between the first pair of conveying rollers and the second pair of conveying rollers.