Image Reading Device Light Source Intensity Control
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Solution Overview
Problem
Conventional image-reading devices face issues with light source temperature rise during inter-sheet periods, leading to decreased light intensity and image quality, and instability when the light source is turned off and relit, affecting the quality of scanned images.
Innovation Solution
An image-reading device with a control unit that adjusts the light source intensity to a lower level during inter-sheet periods, using a conveying unit to manage sheets along a conveying path with a reading unit and light source, ensuring consistent image quality by maintaining the light source's temperature and stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the light source is kept on during inter-sheet periods at the same intensity used during reading periods, then the light intensity remains stable, but the temperature of the light source rises and light intensity decreases
Solution Approach 1:
The patent applies dynamics by making the light source intensity adjustable and time-dependent. The control unit dynamically changes the light intensity between a first intensity during reading periods and a second lower intensity during inter-sheet periods. This dynamic adjustment allows the system to maintain adequate lighting for image reading while reducing temperature rise during idle periods, thereby resolving the contradiction between light intensity stability and temperature control.
Solution Approach 2:
The patent changes the operational parameters of the light source based on the reading cycle. Specifically, it modifies the light intensity parameter from a constant high value to a variable value that switches between a first intensity (during reading) and a second lower intensity (during inter-sheet periods). This parameter change enables the system to balance light intensity requirements with temperature management, preventing excessive heat accumulation while maintaining reading quality.
2Temperature
If the light source is turned off during inter-sheet periods, then the temperature is controlled, but the light intensity does not stabilize immediately when relit
Solution Approach 1:
The patent uses dynamics by implementing a three-state light control strategy: (1) first intensity during reading periods, (2) second lower intensity during inter-sheet periods, and (3) gradual transition back to first intensity when the next sheet is ready. This dynamic approach allows the light source to remain partially active during inter-sheet periods, maintaining warmth without excessive temperature rise, and enables a smoother transition to full intensity when needed, reducing stabilization time.
Solution Approach 2:
The patent applies preliminary action by keeping the light source at a reduced but non-zero intensity during inter-sheet periods. This preliminary maintenance of light emission prevents the light source from completely cooling down, so when the next reading period begins, the light intensity can stabilize more quickly. The system prepares the light source in advance by maintaining minimal activity, thus avoiding the delay that would occur if the light were completely turned off.
3Temperature
If the light source intensity is reduced during inter-sheet periods, then temperature rise is suppressed, but image reading cannot be performed
Solution Approach 1:
The patent resolves this contradiction through dynamic light intensity control that adapts to the operational state. During inter-sheet periods when no reading is occurring, the light intensity is reduced to a second level that suppresses temperature rise. When a sheet is detected and reading is required, the system dynamically switches back to the first intensity level, ensuring full reading capability is restored. This dynamic switching allows the system to optimize temperature management during idle periods while maintaining complete productivity during active reading periods.
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 solution effectively suppresses light source temperature rise and reduces the time required for light stabilization, thereby maintaining image quality and preventing intensity drops, ensuring consistent scanning performance.
Implementation Method 1
a light source configured to emit a light toward the first reading position
Implementation Method 2
a light-receiving unit configured to receive a reflected light emitted by the light source and reflected from the first reading position
Data Source
AI summary
An image reading device includes a conveying unit, reading unit, and a control unit. The conveying unit conveys successive two sheets along a conveying path such that a gap is formed between the successive two sheets. The reading unit reads a sheet conveyed at a reading position in the conveying path. The reading unit has a light source and light-receiving unit. The control unit controls the light source to emit light at a first light intensity for a sheet that has reached the reading position. The light-receiving unit receives light reflected by the sheet present at the reading position. The control unit further controls the light source to emit a light at a second light intensity lower than the first light intensity during a period of time from when the reading unit has been read the preceding sheet to when the reading unit begins reading the subsequent sheet.