Sheet Bending Detection in Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses struggle to accurately control the loop amount of sheets with varying types and stiffness, leading to detection errors and image defects.
Innovation Solution
An image forming apparatus equipped with a detection unit that includes a pivot portion and a rotary encoder to detect the bending amount of sheets, allowing for real-time control of the conveyance speed to adjust the loop amount based on the sheet type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single loop detection sensor is used, then the device complexity is reduced, but the measurement precision of loop amount is insufficient for various sheet types
Solution Approach 1:
The patent employs a dynamic detection approach where the detection unit measures loop amount at multiple discrete positions along the sheet conveyance path. By capturing loop amounts at multiple positions and selecting the maximum value, the system achieves high measurement precision for various sheet types without requiring multiple simultaneous sensors, thus maintaining simplicity while improving accuracy.
2Measurement precision
If multiple loop detection sensors are disposed to detect various loop amounts, then the measurement precision is improved, but the device complexity increases due to positioning requirements
Solution Approach 1:
The patent segments the loop detection function into multiple discrete measurement positions along the sheet conveyance path. Instead of using multiple simultaneous sensors requiring complex positioning, the system sequentially measures loop amounts at different positions and selects the maximum value, achieving comprehensive detection with simplified device configuration.
3Difficulty of detecting and measuring
If the loop detection sensor contacts the sheet to detect loop amount, then the detection capability is improved, but image defects and wrinkles occur due to sheet deformation
Solution Approach 1:
The patent introduces a detection unit that functions as an intermediary measurement device. Rather than directly contacting or deforming the sheet, the detection unit measures loop amount at multiple positions along the conveyance path by detecting sheet position indirectly, thereby eliminating image defects and wrinkles while maintaining detection capability.
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 apparatus effectively controls the bending amount of sheets, reducing image defects and wrinkles, and ensuring accurate detection across various sheet types and stiffness.
Implementation Method 1
a rotary encoder configured to output a pulse signal in accordance with a pivot amount of the pivot portion
Data Source
AI summary
An image forming apparatus includes a transfer portion configured to transfer a toner image onto the sheet, a fixing unit configured to fix the toner image transferred by the transfer portion on the sheet, a detection unit arranged between the transfer portion and the fixing unit in a sheet conveyance direction and configured to detect a bending amount of the sheet nipped by the transfer portion and the fixing unit, and a control unit configured to control a conveyance speed of the sheet conveyed by the fixing unit based on a detection result of the detection unit. The detection unit includes a pivot portion configured to pivot when pressed by the sheet nipped by the transfer portion and the fixing unit, and a rotary encoder configured to output a pulse signal in accordance with a pivot amount of the pivot portion.