Lifted Reading Sensor and Guide Layout for Curl-Prone Sheet Scanning
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Solution Overview
Problem
In image forming systems, the close proximity of the image reading sensor to the conveyance surface leads to potential sheet conveyance failures due to sheet curling or floating, damaging the conveyance guide and reducing the ease of attaching and detaching the image reading device.
Innovation Solution
An image reading device with a lifting mechanism that adjusts the reading sensor's height and a conveyance guide that displaces between guiding and retracted postures, allowing the sensor to read images without interfering with sheet conveyance and preventing damage to the conveyance surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the image reading surface is arranged very close to the conveyance surface to improve image reading accuracy, then image reading precision is improved, but the sheet may get caught in the reading sensor when the leading edge curls or floats up, causing conveyance failure
Solution Approach 1:
The conveyance guide is designed to dynamically change its position between a retracted posture (separated from the conveyance surface by a predetermined interval) and a guiding posture (closer to the conveyance surface). This dynamic adjustment allows the system to maintain both image reading precision and conveyance reliability by adapting the guide's position to the operational state.
Solution Approach 2:
The lifting device preliminarily adjusts the reading sensor to a non-reading height (separated from the conveyance path) when image reading is not required. This preliminary action prevents potential sheet conveyance failures before they can occur by ensuring the sensor does not interfere with sheet passage during normal conveyance operations.
2Reliability
If a conveyance guide is arranged close to the conveyance surface to guide the sheet leading edge, then sheet conveyance reliability is improved, but the conveyance guide may contact and damage the conveyance surface or become deformed when the image reading device is attached or detached
Solution Approach 1:
The conveyance guide transitions between retracted and guiding postures dynamically. During attachment or detachment of the image reading device, the guide is in the retracted posture (separated by a predetermined interval), preventing contact with the conveyance surface. During image reading, it moves to the guiding posture to ensure reliable sheet conveyance.
Solution Approach 2:
The lifting device acts as an intermediary mechanism that controls the position of the reading sensor and conveyance guide. It mediates between the need for close proximity during image reading and the need for separation during attachment/detachment, enabling safe operation in both states.
3Reliability
If the conveyance guide is arranged close to the conveyance surface to prevent sheet curling issues, then sheet conveyance reliability is improved, but the attaching and detaching ability of the image reading device is lowered
Solution Approach 1:
The system employs dynamic positioning where the conveyance guide and reading sensor are retracted during attachment/detachment operations and only move to the guiding/reading position when needed. This dynamic behavior eliminates interference during maintenance operations while maintaining reliability during operation.
Data Source
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AI summary
An image reading device (59) reads an image on a sheet conveyed along a conveyance path (49). The image reding device (59) includes a reading sensor (91), a lifting device (83), and a conveyance guide (85). The reading sensor (91) optically reads the image. The lifting device (83) lifts and lowers the reading sensor (91) to a reading height which is close to the conveyance path (49) and at which the image can be read and a non-reading height which is separated from the conveyance path (49) more upwardly than the reading height. The conveyance guide (85) is disposed above the conveyance path (49) and guides the sheet to an image reading position by the reading sensor (91). The conveyance guide (85) is pushed down by the reading sensor (91) lowered to the reading height, and is displaced from a retracted posture separated upward from the conveyance path (49) with a predetermined interval to a guiding posture closer to the conveyance path (49) than the retracted posture.