Cover-Actuated Jam Detection for Image Forming Apparatus
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Solution Overview
Problem
Conventional image forming apparatuses face high production costs and difficulties in detecting and preventing printing paper jams, which can cause damage to the heat roller and make jam removal challenging due to the expense and malfunction of out-feed sensors.
Innovation Solution
An image forming apparatus with a lower cover that opens when a printing medium jam occurs, triggering a printing medium jam detection unit operated by an upper cover, which includes a pressure portion, plunger, spring, operation lever, and switch to detect and signal the jam without the need for an expensive out-feed sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an out-feed sensor is used to detect printing paper jam, then the jam detection capability is improved, but the production cost increases
Solution Approach 1:
The patent replaces the expensive out-feed sensor with a simple mechanical switch integrated into the cover structure. This switch uses ordinary electrical components and mechanical elements that are inexpensive to manufacture, thereby reducing production cost while maintaining jam detection functionality through the cover's opening/closing action during jam conditions
Solution Approach 2:
The cover structure itself serves the dual function of protecting internal components and detecting jams. When paper is jammed, the physical pressure causes the cover to open, which automatically triggers the switch without requiring separate sensor systems. The mechanical structure performs both protective and detection functions simultaneously
2Reliability
If an out-feed sensor is used to detect printing paper jam, then the jam detection capability is improved, but the device complexity increases
Solution Approach 1:
The patent merges the cover structure with the detection mechanism by integrating the switch directly into the cover assembly. This combination eliminates separate sensor systems and reduces overall device complexity while maintaining effective jam detection through the mechanical interaction between the cover and jammed paper
3Productivity
If the lower cover is made to open easily, then the jam detection responsiveness is improved, but the structural stability deteriorates
Solution Approach 1:
The lower cover is designed with dynamic characteristics that allow it to remain stable during normal operation but open readily when jam pressure is applied. The spring mechanism provides elastic deformation that enables the cover to return to its closed position after jam clearance, maintaining structural stability while ensuring responsive jam detection through controlled mechanical flexibility
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 senses and prevents serious printing medium jams, reducing production costs and minimizing damage to the heat roller by using a cost-effective detection system that opens and closes covers to activate the jam detection unit, allowing for efficient removal of jammed paper.
Implementation Method 1
a spring in contact with the plunger, an operation lever connected to the spring, and a switch located in the main frame at a position facing the operation lever to perform opening and closing operations
Data Source
AI summary
An image forming apparatus and a method of sensing a printing medium jam in the image forming apparatus. The image forming apparatus includes a developing unit, a transfer unit, a fixing unit, a feed-out unit, a lower cover to come in contact with a printing medium when the printing medium is jammed on a feed path and which opens upwards when a pressure of the printing medium caused by the printing medium jam is greater than a predetermined reference value, an upper cover to be opened by the contact of the lower cover when the lower cover opens, and a printing medium jam detection unit operated by the upper cover.