Manual Feed Tray Sheet Detection LED Control
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Solution Overview
Problem
Conventional image forming apparatuses face issues with accurately detecting sheet presence and size on manual feed trays due to sheet curl, leading to rapid deterioration of light emitting diodes (LEDs) used in reflection-type sensors, resulting in incorrect detection and increased power consumption.
Innovation Solution
An image forming apparatus with a manual feed tray that includes a first detection unit for sheet presence, a second detection unit with a light emitting and receiving element for sheet length detection, and a control unit that manages the LED's on/off state based on the sheet's state, allowing the apparatus to switch between power modes to minimize LED usage and prevent incorrect detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light emitting element is frequently turned on to detect sheet size after returning from power saving mode, then sheet size detection is enabled, but the light emitting element deteriorates rapidly reducing detection distance
Solution Approach 1:
The system performs sheet presence detection before entering power saving mode, and records whether a sheet is present. When returning from power saving mode, the light emitting element is only activated if the recorded state indicates no sheet was present, avoiding unnecessary activation and extending LED life while maintaining detection capability when needed.
Solution Approach 2:
The system uses feedback from the first detection unit (presence detection) to control the operation of the second detection unit (size detection). The control unit decides whether to activate the light emitting element based on the sheet presence state, creating a feedback mechanism that optimizes LED usage and prevents deterioration.
2Measurement precision
If the light emitting element is turned on every time after returning from power saving mode, then sheet size can be detected, but power consumption increases
Solution Approach 1:
The system performs preliminary sheet presence detection before entering power saving mode and stores this information. Upon returning from power saving mode, it uses the stored information to determine whether size detection is necessary, thereby avoiding unnecessary power consumption from the light emitting element while ensuring detection when actually needed.
Solution Approach 2:
Instead of always activating the full size detection function (light emitting element) after power saving mode, the system applies partial action by only activating it when sheet presence changes occur. This reduces overall power consumption while maintaining sufficient detection capability for actual needs.
3Measurement precision
If transmission-type sensor with light shielding flag is used, then sheet presence can be detected, but sheets with edges not in contact with sheet tray (curled sheets) cannot be correctly detected
Solution Approach 1:
The detection function is segmented into two independent units: the first detection unit (transmission-type with light shielding flag) for detecting sheet presence, and the second detection unit (reflection-type with light emitting element) for detecting sheet size. Each unit handles specific detection tasks, allowing the system to detect both normal and curled sheets effectively.
Solution Approach 2:
The first detection unit acts as an intermediary that triggers the operation of the second detection unit. When the first unit detects sheet presence (including curled sheets), it activates the second unit to perform size detection, enabling the system to handle various sheet states through coordinated operation of multiple detection mechanisms.
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
This solution effectively reduces the deterioration of LEDs by controlling the LED's usage, minimizing incorrect sheet size detection and power consumption, while ensuring accurate sheet detection even with curled sheets.
Implementation Method 1
The sensor of this type irradiates light on a target from light emitting element to detect reflected light
Data Source
AI summary
An image forming apparatus which can control to turn on/off a light emitting element depending on a sheet state on a manual sheet tray is provided. The image forming apparatus includes the manual feed tray on which the sheet is placed. The image forming apparatus is configured to be switchable between normal power mode and power saving mode. In the normal power mode, normal power is supplied. In the power saving mode, less power is consumed as compared to the power consumed in the normal power mode. The image forming apparatus includes a manual sheet feeding sensor which detects presence/absence of the sheet on the manual feed tray. The image forming apparatus includes a sheet length sensor S and a sheet length sensor L which include the light emitting element and a light receiving element to detect approximate sheet length of sheet placed on the manual feed tray in a conveying direction.