Cover Open State Detection in Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses often provide incorrect user notifications regarding the open state of covers due to shared signal lines and design convenience assigning safety signals, leading to misidentification of which cover is open.
Innovation Solution
Implementing a control method that delays notifications for a predetermined period when a cover is opened, allowing for accurate determination of open states by prioritizing switch signals from individual cover switches over shared interlock switches, and displaying specific notification screens to prevent incorrect user information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a shared signal line is used for interlock switches of multiple covers, then device complexity is reduced, but measurement precision of cover open state detection deteriorates
Solution Approach 1:
The patent segments the signal detection process by introducing a controller that individually evaluates signals from each interlock switch (first interlock switch for front cover, second interlock switch for ADU cover) rather than using a shared signal line. This segmentation allows precise identification of which specific cover is open, resolving the ambiguity while maintaining relatively simple hardware architecture.
Solution Approach 2:
The controller acts as an intermediary that receives signals from multiple interlock switches through a shared signal line but processes them to determine the specific open cover state. The controller mediates between the simple shared signal line configuration and the need for precise cover identification, enabling accurate detection without requiring separate dedicated signal lines for each switch.
2Ease of operation
If safety signals are assigned to individual covers for design convenience, then ease of operation is improved, but reliability of open state notification deteriorates
Solution Approach 1:
The patent implements feedback by having the controller continuously monitor the states of both the first interlock switch and the second interlock switch, and the respective cover switches. The controller uses this feedback to dynamically determine which cover is actually open and provides corresponding notifications, ensuring reliability while maintaining the convenience of the signal assignment structure.
Solution Approach 2:
The system dynamically adapts its notification behavior based on the actual cover states detected by the switches. Rather than being static in its notification logic, the controller flexibly responds to different combinations of switch states, allowing it to reliably identify the open cover regardless of which safety signal assignment convention is used.
3Productivity
If notifications are sent immediately when a cover is opened, then productivity is improved, but loss of information increases
Solution Approach 1:
The controller performs preliminary detection and verification of the open cover state before generating notifications. It first detects which interlock switch is activated and verifies the corresponding cover switch state, ensuring accurate identification before sending the notification. This preliminary action prevents information loss while maintaining efficient notification timing.
Data Source
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AI summary
An image forming apparatus has a controller with a first input terminal configured to receive a first signal indicating a state of a first opening/closing portion, a second input terminal configured to receive a second signal indicating a state of a second opening/closing portion, and a third input terminal configured to receive a third signal indicating a state of the first opening/closing portion and the second opening/closing portion. The controller is configured to delay a first notification of an open state of the first opening/closing portion and a second notification of an open state of the second opening/closing portion for a predetermined period after any one of the first signal, second signal, or third signal initially indicates an open state.