Optical Sensor Arrangement for Imaging Apparatus Toner Tracking
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Solution Overview
Problem
Existing imaging apparatuses with toner cartridges experience print defects due to continuous and varying forces applied by mechanical sensors, which are not suitable for accurately tracking toner addition cycles without imparting excessive force on the cartridge.
Innovation Solution
An optical sensor arrangement with a cam and flag mechanism that applies intermittent force, using a rotatable shaft and optical path blocking/unblocking to count toner addition cycles, reducing the overall force on the toner cartridge and minimizing print defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanical sensor with continuous contact (pogo pin and spring) is used to track toner addition cycles, then the number of TAC's can be counted, but a large and varying force is continuously applied on the toner cartridge causing print defects
Solution Approach 1:
The patent replaces the mechanical contact sensor system with an optical sensing system. An optical sensor detects the rotation of the cam through non-contact means, eliminating the need for continuous mechanical contact and the associated large varying forces on the toner cartridge while maintaining TAC counting accuracy
Solution Approach 2:
The patent uses intermittent mechanical contact where the cam only engages the flag during specific portions of its rotation to trigger optical sensor detection. This periodic engagement applies force only when necessary for counting TAC's, significantly reducing the overall continuous force on the cartridge compared to constant mechanical contact
2Reliability
If a mechanical sensor with spring bias is used to track TAC's, then the sensor remains in constant contact with the cam, but this continuous contact imparts varying force that results in print defects
Solution Approach 1:
The patent replaces the mechanical spring-biased contact sensor with an optical sensor system that detects cam rotation without physical contact. This eliminates the harmful forces transmitted to the toner cartridge that cause print defects while maintaining reliable detection of TAC events through optical signal changes
Solution Approach 2:
The patent introduces an optical field as an intermediary between the cam and the sensor. The optical sensor detects cam position or rotation through light interaction rather than direct mechanical contact, serving as a mediator that provides reliable detection without transmitting harmful forces to the cartridge
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 optical sensor system effectively tracks toner addition cycles with reduced force on the toner cartridge, minimizing print defects and providing accurate toner level estimation, as tested with a force range of 8-12 grams-force and torsion of approximately 0.6 N*mm.
Implementation Method 1
The optical sensor has an output that changes when the optical path changes from blocked to unblocked and from unblocked to blocked
Data Source
AI summary
An imaging apparatus includes a toner cartridge within a housing having a rotatable shaft, a cam rotatably mounted on the shaft, an optical sensor mounted on the housing having an emitter and a receiver forming an optical path therebetween, and a flag mounted on the housing having a first arm and a second arm. The optical sensor has an output that changes when the optical path changes from blocked to unblocked and from unblocked to blocked. The flag has a home position where the first arm is disposed in the rotational path of the cam and the second arm either blocks the optical path or unblocks the optical path. Rotation of the rotatable shaft causes the cam to engage and disengage the first arm causing the second arm to change from blocking the optical path to unblocking the optical path or vice versa.