Printer Work-Area Interlock Using Shutter and Contact Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional safety interlocks on printing apparatus doors can trap workers inside the exterior part, posing a safety risk during maintenance.
Innovation Solution
A printing apparatus with a sensing mechanism to detect when a worker is in a contactable state with the work target, and an operation limiting mechanism to restrict the printing section's operation in such cases, using a shutter to shield the work area and an interlock system to ensure the carriage is not operational when the door is open.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an interlock is provided on the door of the exterior part to limit operation when the door is opened, then safety is improved by preventing operation during maintenance, but the worker may be trapped inside the exterior part
Solution Approach 1:
A shutter is introduced as an intermediary element between the door and the printing section. The shutter can be opened to allow worker access to the printing section even when the door is open and interlock is active, while still maintaining safety by allowing controlled access rather than complete exposure to moving parts
Solution Approach 2:
The system dynamically adjusts operation limiting based on real-time detection of worker position. When the sensing means detects a worker in the exterior part, the operation limiting means selectively restricts printing section operation, but allows door opening and shutter operation. This dynamic response prevents trapping while maintaining safety
2Reliability
If the printing section operation is limited when a worker is detected in the contactable state, then worker safety is improved, but productivity is reduced due to operational restrictions
Solution Approach 1:
The operation limiting means implements partial action by selectively restricting only the printing section operation while allowing other essential functions to continue. The door can still open, the shutter can operate, and maintenance activities can proceed, thereby limiting safety risks without completely halting system productivity
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A printing apparatus (1) includes, a printing section (20) that prints on a recording medium; an exterior part (40) that covers the printing section; a work area (41) that is defined inside the exterior part and in which a worker performs work on a work target (21); a sensing means (64) for sensing a contactable state in which a human can contact the work target from the work area; and an operation limiting means (65) configured to limit an operation of the printing section in a case in which the sensing means senses the contactable state.