Sheet Detection Mechanism Optical Path Air Cooling
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Solution Overview
Problem
Existing sheet detection mechanisms in image forming apparatuses using electrophotographic techniques face issues with dew condensation and thermal damage due to water vapor and heat from the fixing unit, leading to potential malfunction and require air cooling, which complicates the design and increases the size of the apparatus.
Innovation Solution
A miniaturized air blow configuration for the sheet detection mechanism, where air is blown from the first guide unit to the second guide unit, hitting the optical elements and preventing dew condensation and thermal damage, while maintaining the optical path and air duct lengths as short as possible to reduce power consumption and prevent image damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the sheet detection mechanism is disposed near the fixing unit, then the apparatus size is reduced, but dew condensation and thermal damage occur to the sensor
Solution Approach 1:
The sensor unit is divided into separate components: a light emitting unit and a light receiving unit, which are disposed on opposite sides of the sheet conveyance path. This segmentation allows the sensor to be positioned closer to the fixing unit while maintaining functional separation and reducing thermal interference with individual sensor components.
Solution Approach 2:
Air is introduced as an intermediary medium between the fixing unit and the sensor unit. The air flow acts as a thermal barrier, preventing heat and water vapor from the fixing unit from reaching the sensor unit, thereby preventing dew condensation and thermal damage while allowing the sensor to be positioned near the fixing unit.
2Reliability
If air is blown to cool the sensor unit, then dew condensation is prevented, but the apparatus becomes larger due to additional air ducts
Solution Approach 1:
The guide units that are already present for sheet conveyance are made to serve dual functions: guiding the sheet through the apparatus and serving as air ducts to direct cooled air to the sensor unit. This eliminates the need for separate air duct structures, maintaining sensor cooling functionality while avoiding increased apparatus complexity.
Solution Approach 2:
The air cooling function is merged with the existing guide unit structure. The guide units are configured to simultaneously perform sheet guidance and air flow channeling, combining two functions into a single structural element and avoiding additional components.
3Measurement precision
If the sensor unit is disposed on both guide units, then detection accuracy is improved, but the apparatus size increases due to multiple air ducts
Solution Approach 1:
The guide units are designed to serve multiple purposes: they guide the sheet through the apparatus, support the sensor units, and function as air ducts for cooling. This multi-functionality allows the sensor unit to be disposed on both guide units for improved detection accuracy without requiring additional air duct structures that would increase apparatus size.
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 prevents dew condensation and thermal damage to the optical elements, allowing for a more compact design of the image forming apparatus while maintaining detection accuracy and reducing power consumption.
Implementation Method 1
a light-emitting unit is arranged on one of the guide units, and a light-receiving unit for receiving light and converting it into an electrical signal is arranged on the other guide unit
Implementation Method 2
a light-receiving unit for receiving light and converting it into an electrical signal is arranged on the other guide unit
Implementation Method 3
the first guide unit is provided with a duct for sending air to the first optical element unit, and air coming out from the first opening portion hits the second optical element unit via the second opening portion
Data Source
AI summary
According to the present disclosure, a first guide unit is provided with a first opening portion through which light in an optical path connecting a first optical element unit and a second optical element unit passes, a second guide unit is provided with a second opening portion through which light in the optical path connecting the first optical element unit and the second optical element unit passes, the first guide unit is provided with a duct for sending air to the first optical element unit, and the air coming out from the first opening portion hits the second optical element unit via the second opening portion.